2022 Routine Inspection ME Final Report.pdf

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Buzzards Bay Vertical Lift Railroad Bridge

Buzzards Bay, Massachusetts

2022 Routine Inspection of Movable Bridge

Mechanical and Electrical Operating Systems

Inspection Date: March 7th-11th and April 8th, 2022

PREPARED FOR:

Department of the Army, US Army Corps of Engineers

New England District

696 Virginia Road

Concord, Massachusetts 01742-2751

PREPARED BY:

Wiss, Janney, Elstner Associates, Inc.

800 Hyde Park

Doylestown, Pennsylvania 18902

800 Hyde Park

Doylestown, Pennsylvania 18902

2022 Routine Inspection of Movable Bridge

Inspection Date: March 7th-11th and April 8th, 2022

PREPARED FOR:

Department of the Army, US Army Corps of Engineers

New England District

696 Virginia Road

Concord, Massachusetts 01742-2751

PREPARED BY:

Wiss, Janney, Elstner Associates, Inc.

800 Hyde Park

Doylestown, Pennsylvania 18902

800 Hyde Park

Doylestown, Pennsylvania 18902

Ryan Kanagy

Lead Mechanical Inspector

Robert McPherson

Lead Electrical Inspector

2022 Routine Inspection of Movable Bridge

Mechanical and Electrical Operating Systems

INSPECTION DATE: MARCH 7TH-11TH AND APRIL 8TH, 2022

TABLE OF CONTENTS

EXECUTIVE SUMMARY

INTRODUCTION

DESCRIPTION OF SYSTEMS

MECHANICAL INSPECTION FINDINGS

SPAN DRIVE MACHINERY

Motors

Brakes

Open Gearing

Couplings

Span Drive Bearings

Center Span Drive Clutch Differentials

MAIN COUNTERWEIGHT SHEAVE ASSEMBLIES

MAIN COUNTERWEIGHT WIRE ROPES

AUXILIARY COUNTERWEIGHT SHEAVE ASSEMBLIES

AUXILIARY COUNTERWEIGHT ROPES

LOWER SPAN LOCKS

Lock Bars, Guides and Receivers

Parallel Gear Reducers

Right-Angle Reducers

Open Gearing

Couplings

Bearings

Linkages

UPPER SPAN LOCKS

AIR BUFFERS

LIVE LOAD SUPPORTS

CENTERING DEVICES

SPAN GUIDES

MAIN COUNTERWEIGHT GUIDES

AUXILIARY COUNTERWEIGHT GUIDES

2022 Routine Inspection of Movable Bridge

Mechanical and Electrical Operating Systems

INSPECTION DATE: MARCH 7TH-11TH AND APRIL 8TH, 2022

MITRE RAILS

SPAN BALANCE

VIBRATION TESTING

MECHANICAL CONCLUSIONS

MECHANICAL RECOMMENDATIONS

ELECTRICAL INSPECTION FINDINGS

ELECTRICAL SERVICE

EMERGENCY GENERATOR

MOTOR CONTROL CENTER

PANELBOARDS AND TRANSFORMERS

BRIDGE CONTROL SYSTEM

Main Control Cabinet

Remote Control Cabinets

Control Desk

BRIDGE OPERATION

Main Drive Motor Controls

Auxiliary Drive Motor Controls

Brake Control

Span Lock Control

Train Signal Interlock

Control Interlock Bypass

LIMIT SWITCHES

Brake Limit Switches

Upper Locks Limit Switches

Lower Span Lock Limit Switches

Span Fully Open Limit Switches

Span Fully Seated Limit Switches

Auxiliary Drive Limit Switches

Rotary Limit Switch and Height Transmitter

Railroad Signal Switches

MOTORS

Main Drive Motors

2022 Routine Inspection of Movable Bridge

Mechanical and Electrical Operating Systems

INSPECTION DATE: MARCH 7TH-11TH AND APRIL 8TH, 2022

Auxiliary Drive Motors

Differential Clutch Motors

Lower Span Lock Motors

Upper Span Lock Motors

BRAKES

Motor Brakes

Machinery Brakes

NAVIGATION LIGHTS AND SIGNALS

Aviation Beacons

Navigation Lights

Signal Horn

Lighting

CCTV SYSTEM

AERIAL CABLES

MISCELLANEOUS WIRINGS AND RACEWAYS

GROUNDING

ELECTRICAL CONCLUSIONS

ELECTRICAL RECOMMENDATIONS

APPENDIX A. FIGURES

APPENDIX B. MECHANICAL INSPECTION PHOTOS

APPENDIX C. MECHANICAL TABLES

APPENDIX D. FLUID ANALYSIS REPORT

APPENDIX E. MECHANICAL FIELD NOTES

APPENDIX F. MAIN COUNTERWEIGHT ROPE TENSION REPORT

APPENDIX G. SPAN BALANCE ANALYSIS REPORT

APPENDIX H. VIBRATION TESTING REPORT

APPENDIX I. ELECTRICAL INSPECTION PHOTOS

APPENDIX J. ELECTRICAL RECORDINGS

APPENDIX K. ELECTRICAL INSULATION RESISTANCE MEASUREMENTS

APPENDIX L. STATUS OF 2016 ELECTRICAL RECOMMENDATIONS

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EXECUTIVE SUMMARY

Wiss, Janney, Elstner Associates, Inc. (WJE) performed a routine mechanical and electrical inspection on the

Buzzards Bay Vertical Lift Railroad Bridge in March and April 2022. The inspection included a review of the mechanical and electrical systems, strain gage balance testing, an evaluation of the main counterweight rope tensions, and structural vibration analysis.

The bridge mechanical systems were found to be in fair condition overall. The most significant mechanical issue noted during the inspection was damage at the lower span locks. The north span lock receivers had failed and no longer perform as designed. The locks will not restrain the bridge. This was discussed with maintenance at the time of the inspection and should be corrected in the near term. In addition, the manual shaft extensions at the lower span lock right-angle reducers were not usable due to severe section loss from corrosion. Maintenance personnel noted that these reducers, along with the lower lock motors and couplings, are scheduled for near term replacement.

The span drive machinery was operated without issue during the inspection. Strain gage testing results indicate an increase in imbalance compared to the balance condition reported in 2016. Although the increased load is well within the capacity of the machinery, consideration should be given to adjusting the span balance to match desired balance condition. Through analysis of the strain gage balance data, it is apparent that the efficacy of the southwest corner differential has deteriorated since the 2016 inspection.

An issue with this differential has been apparent historically, but consideration may be given to rehabilitating the assembly or, as a minimum, attempting to flush and or lubricate the seized bearings internal to the assembly.

The motor and machinery brakes set without any mechanical time delay which will result in undesirable shock loading of the machinery under emergency stop conditions. Additionally, the machinery brake torque settings generally do not match requirements from available drawings. The proper settings of the brakes should be set based on an investigation and the time delays should be adjusted.

Lubrication was generally fair but with several issues that require maintenance attention. Oil analyses performed on the lower span lock parallel shaft reducers indicated the presence of water and metallic wear particles. These units should be flushed, provided with new oil, and monitored for contamination.

The span drive and span lock couplings are not regularly lubricated. These couplings should be flushed with lubricant yearly. The main and auxiliary counterweight ropes were insufficiently lubricated at the time of the inspection.

The support systems were generally in fair condition with minor corrosion as the most significant issue.

There are snapping sounds from both northwest counterweight sheave trunnion and bearing assemblies during operation. Despite the sounds, there was no fretting or other evidence of significant movement at the sheave and trunnion interfaces or at the dowels which are also used to secure the sheaves to the trunnions. These noises are not expected to impact reliable operation of the bridge.

The air buffers were in fair external condition, but they may not function as designed as they do not appear to generate any pressure based on the installed gages. The air buffer systems should be rehabilitated as necessary to return them to service and ensure they work properly in the event that the bridge comes to the fully raised or seated position without slowing.

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Vibration testing was performed to determine displacements of the lift span and tower structures due to vibrations during rail traffic and during lift span operation. Many of the results were found to be similar to

2010 and 2016 testing, though calculated displacements at multiple events were higher than expected given the nature of the system. It is likely that some of the data had been negatively affected by non-vibratory loads such as impact loads and other accelerations.

Counterweight rope tensions were calculated and compared to the averages for each corner and each tower. The rope tension calculations indicate that an adjustment to the counterweight ropes is not necessary at this time.

The electrical and control systems for the bridge were in good physical and operating condition with the exception of an issue when attempting to operate on the auxiliary drive. This issue, described in the auxiliary drive section of the report, should be fully investigated, and corrected.

The electric utility service and emergency backup generator were in good service condition. The insulation resistance tests for electrical machinery motors and associated feeder circuits show results well above acceptable values according to the Inter-National Electrical Testing Association (NETA) Standard for

Maintenance Testing Specifications for Electrical Power Equipment. The feeder conductor and motor winding insulation resistance testing show that the equipment was suitable for continued service. The electrical machinery equipment operating voltage, current, and power demand characteristics are within equipment ratings and indicate normal operating condition. Although the upper span lock motor insulation resistance values were acceptable at the time of the inspection, their insulation resistance were significant lower compared to 2016 test results. It is recommended to monitor their insulation condition in the near term.

Several findings require modifications or repairs to bring the systems into compliance with the National

Electrical Code. These findings include missing local disconnect switches for all main drive motors, working clearances issues, missing arc flash hazard warning labels, and additional maintenance and repair items indicated in the body of this report and in the electrical recommendations.

With maintenance efforts to correct the deficiencies noted in this report, the bridge mechanical and electrical systems should provide for long term reliable service.

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INTRODUCTION

The Buzzards Bay Vertical Lift Railroad Bridge is a through-truss tower drive vertical lift bridge over the

Cape Cod Canal in Bourne, Massachusetts. Wiss, Janney, Elstner Associates, Inc. (WJE) performed a routine mechanical and electrical inspection on the Buzzards Bay Vertical Lift Railroad Bridge on March 7th through 11th and April 8th, 2022. The inspection included a review of all mechanical and electrical systems, strain gauge balance testing, an evaluation of the main counterweight rope tensions, and structural vibration analysis. This report summarizes the findings of the inspection and provides maintenance and repair recommendations.

Reference material is appended to this report, including figures, photographs, tables, fluid analysis reports, field notes, electrical charts and graphs, nameplate data, and separate stand-alone reports for rope tensions, strain gage span balance analysis, and vibration testing.

DESCRIPTION OF SYSTEMS

The lift span is 544 feet long by 27 feet wide and for the purposes of this report is oriented north-south with the operator’s house at the north end of the bridge. The lift span is normally kept in the raised position and is seated to service railroad traffic.

The machinery for the lift span consists of span drive machinery, span support machinery, span guides, counterweight guides, buffers, span locks, and devices for locating the span during seating. Figures M1 through M4 in Appendix A identify the primary machinery systems.

There is a span drive machinery assembly located at the top of each tower. The machinery comprises motors, brakes, open gears, couplings, and bearings. A pair of 200 HP DC main motors are coupled to either end of the P3 pinion shaft mounted within the primary gear frame. Mounted to the back end of each main motor is a thrustor brake. Each of the output shafts from the primary gear frame drive the P2 pinions in the secondary gear frames. Mounted outboard of the P2 pinion shafts are a second (machinery) thrustor brake. The P2 pinions drive the G2 gears which have a differential. The G2 differentials output to the P1 pinion shafts. Each P1 pinion mates with a ring gear mounted to a main counterweight sheave.

Each tower is also provided with an auxiliary drive system which consists of a 15 HP auxiliary gearmotor, enclosed reducer, and an additional gearset which can be manually engaged with the primary span drive gear train.

The lift span is counterbalanced by two main counterweights, one located within each tower at opposite ends of the span. The span is connected to each counterweight by 40 wire ropes for a total of 80 ropes.

The ropes are divided into groups of 10 with each group being supported by a main counterweight sheave which is mounted at the top of the tower. The ropes transmit the weight of the lift span and counterweights to the structural tower through the main counterweight sheaves. Each sheave is rigidly mounted on a large trunnion shaft that is simply supported in a pair of roller bearings mounted in pillow block housings. As the sheaves rotate, the main counterweight ropes pass from one side to the other resulting in the lift span raising or lowering while the main counterweights travel in the opposite direction.

The bridge is equipped with an auxiliary counterweight system to compensate for the change in imbalance caused by the main counterweight ropes transitioning from the span side to the counterweight side of the main counterweight sheaves. The bridge is provided with two auxiliary counterweights, one

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located within each tower at opposite ends of the span. Each auxiliary counterweight is supported by four wire ropes, two at the east and west ends. The auxiliary counterweight ropes pass over sheaves mounted at the top of the towers and are anchored to upper chords near the middle of the lift span.

The bridge is equipped with a system of lower span locks intended to prevent undesirable upward movement of the lift span when in the seated position. A lower span lock machinery is mounted on each of the piers. Each assembly includes a motor, a pair of reducers, an open gearset, and a crank that actuates a lock bar at each corner of the span. Each lock bar is mounted in a front and rear guide mounted on the pier. When the lock bar is driven, it engages with a receiver mounted on the lift span to prevent upward movement of the span.

The bridge is mainly kept in the fully raised position and is equipped with upper span locks. The upper span locks are provided as a safety measure to prevent the span from lowering. The upper span lock machinery is located near the top of the towers and consists of a hydraulic power unit (HPU), hydraulic cylinder, lock bar and guides mounted on the tower and receiver shoes mounted to each corner of the lift span.

The lift span is equipped with eight air buffers, four upper and four lower. The buffers are intended to reduce shock loading if the bridge approaches the fully raised or seated positions at excessive speed. The upper air buffers are mounted at the bottom of the towers and engage with strike plates on the top flange of the lifting girders. One lower air buffer is mounted adjacent to each live load support at each corner of the bridge.

The span is provided with four live load supports to transmit the imbalance load and the loads due to train traffic from the lift span to the piers. The south end live load supports consist of a saddle mounted on the lift span and pin anchored to the pier. The north end live load supports have a curved shoe pinned to the lift span and a strike plate anchored to the pier. This arrangement allows for the north end of the bridge to accommodate differential thermal expansion.

A centering device is provided at both piers to locate the bridge transversely when seated. The centering device consists of a male base casting mounted to the pier and a female receiver casting mounted to the lift span.

The lift span is equipped with guide rollers to limit undesirable lateral movement during span operation.

Transverse guide rollers are provided at each end of the top and bottom chords and longitudinal rollers are provided at the south end bottom chords. Each roller mates with a guide rail mounted to the tower legs.

The main and auxiliary counterweights have upper and lower sliding type guides at each side that engage guide rails attached to the lift span towers.

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MECHANICAL INSPECTION FINDINGS

SPAN DRIVE MACHINERY

Motors

The span drive machinery in each tower is equipped with two (2) 200 HP, 650/1600 RPM electric motors.

One motor in each tower is used to operate the span.

The main motors were generally in good condition with the only noted deficiencies being accumulation of grease on the motor housings and filters, unpainted and lightly corroded shafts, and paint breakdown and surface corrosion on the mounting bolts. See Photo M1, Appendix B.

Each tower is equipped with one (1) 15 HP, 1800-155 RPM electric auxiliary motor with a Stearns brake mounted to the non-driven end. The auxiliary motors were generally in fair condition. The auxiliary motor housings were covered in light grease overspray from the nearby open gearing. It was noted that the north auxiliary motor nuts for the middle mounting bolts (south side) were not fully seated due to an interference with an adjacent rivet. See Photo M2, Appendix B. This is unchanged from the previous report and no signs of movement were noted.

The nuts and threads at some main motor mounting bolts were not fully painted and light corrosion was noted. See Photo M3, Appendix B.

Brakes

The span drive machinery is equipped with four (4) brakes in each tower; there are two (2) motor brakes and two (2) machinery brakes. All brakes are thrustor released, spring set drum brakes. The motor brakes are located on the non-driven end of each main motor. The machinery brakes are located outboard of bearing B5 on the pinion P2 shaft. Brake shoe contact and brake pad lining thickness were verified to be acceptable at all brake assemblies. It was noted that none of the brakes had a time delay when setting; all brakes set simultaneously. Applying the full braking torque of the machinery without staggering the brakes is undesirable and can shock load the machinery. See Mechanical Table 1 in Appendix C for brake settings, reserve stroke lengths, and shoe thickness measurements.

Generally, the motor brakes were found to be in fair condition. All motor brakes had light surface corrosion on the mounting bolt heads and isolated areas of corrosion on the brake assembly, including the brake rods. In addition, the brake wheel hubs were not painted on their inboard faces and were lightly corroded. The two south mounting bolts for the NE Motor Brake (Brake A) did not fully bear on the support due to an interference with the adjacent weld. See Photo M4, Appendix B. No movement of the brake was noted and corrective action is not warranted at this time. The motor brakes are provided with a scale to indicate the set brake torque. The motor brake torques all exceeded the specified setting of 600 ft-lb provided on the original Design Plans; however, the maximum deviation from the design torque (an increase of 40 ft-lbs or about 6%) is not significant. See Mechanical Table 1, Appendix C. Additionally, the thrustor on the northwest motor brake (Motor Brake B) was found to be overfilled with hydraulic fluid. See

Photo M5, Appendix B.

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The machinery brakes were in fair condition. The brake wheels for Machinery Brakes E and F appeared to orbit as the shafts rotated. There is a wear mark on the center of both brake wheels, apparently from contact with the brake rod. The wear mark was heavier at the northwest machinery brake (Brake F). See

Photo M6, Appendix B. This may be an older condition as no contact between the wheels and linkages was observed during the current inspection. The machinery brakes are not provided with scales to display the set brake torques. The torque is determined by the length of the spring based on the graph in Mechanical

Table 1, Appendix C. The original Design Plans specify a set brake torque of 1200 ft-lb for the machinery brakes. Machinery Brake E and F were set below the specified torque and Machinery Brakes G and H were set well above the specified torque. See Mechanical Table 1, Appendix C.

Open Gearing

The opening gearing was generally found to be in fair condition. The gearing was observed during operation and one representative tooth from each gear was cleaned off for visual inspection. Lubrication was adequate for all open gearing.

The gearing generally exhibited light to moderate levels of pitting, scoring, and plastic flow with isolated areas of more severe wear and/or damage. See Photo M7 and Photo M8, Appendix B. There was evidence of previous cross-bearing misalignment at multiple gear sets that has worn into full face contact. As noted during the 2016 inspection, strain gage data indicates that the southwest differential was not working properly at the time of inspection.

Backlash measurements were taken for all open gear sets and are presented in Mechanical Table 2, Appendix C. The backlash measurements from the 2004, 2006, 2010 and 2016 inspections are provided for historical context. Some measurements vary significantly between inspections, and this is likely attributable to variances in the position of the tooth mesh when the measurements were taken. The backlash measurements taken as part of this inspection do not indicate significant wear or any other issues.

Couplings

The span drive machinery in each tower is equipped with four couplings; one is a grid type coupling that connect the auxiliary gearmotor to the P4 shaft, two are double engagement gear couplings connecting the primary motor shafts to the P3 shaft, and one is a jaw type coupling that connects the auxiliary drive motor to the auxiliary drive reducer.

The span drive couplings were in fair condition. The couplings were visually inspected and observed during operation. All fasteners were verified to be present and tight. The lubrication port plugs had been painted over, which would indicate that the couplings have not been lubricated at least since they were painted. Maintenance personnel should ensure that the couplings are periodically lubricated. See Photo

M9, Appendix B.

Span Drive Bearings

Each tower is equipped with twenty (20) bearings to support the span drive machinery. Each bearing is a bronze-bushed plain bearing in a pillow block housing. The bearings were generally found to be in fair

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condition. The bearings were visually inspected and observed during operation. No movement or other issues were noted during operation.

Missing lock nuts at some south bearings (including the B10 bearings) and skew control machinery bearing were noted in previous inspections. This condition was unchanged, though there is no movement at these connections and no corrective action is warranted.

Center Span Drive Clutch Differentials

Each tower is equipped with one (1) center span drive clutch differential. Maintenance personnel indicated that the mechanisms for the center span drive clutch differentials have not been functional for years. This system was provided with a cursory inspection. No significant mechanical issues were noted. The purpose of the center span drive clutch differential is to allow for indexing between the west and east portions of the machinery within the tower. The indexing would be used to address load sharing and/or seating issues.

Apart from the poor load sharing between the two ring gears at the southwest corner (attributed to an improperly functioning southwest corner differential), there were no apparent issues with east-west load sharing during operation or with seating. Additionally, personnel on site noted that there have been difficulties in the past trying to return the center clutch differentials to service. Given the reported difficulties and that there are no negative operational issues attributed to the inoperable center differentials, repairs are not recommended at this time.

MAIN COUNTERWEIGHT SHEAVE ASSEMBLIES

The main counterweight sheave assemblies were in fair condition. The assemblies were visually inspected and observed during operation. The sheaves were well painted, except for the rope grooves which are not protected with lubricant and had light surface corrosion. See Photo M10, Appendix B. The rope grooves were smooth with no evidence of significant wear noted.

The undersides of multiple trunnion bearing mounting bolts were not painted and were corroded. Note that the mounting bolts were inaccessible for inspection at some locations.

At each of the trunnion bearings, excess lubricant had pushed out of the sheave side of the bearing and collected in the drip tray below. Minor lubrication leakage was noted at the bearing cover plate at the north TB4 assembly. See Photo M11, Appendix B .

Snapping sounds emanated from both northwest inboard and outboard counterweight sheave assemblies during operation. The noises noted were similar to those noted during the 2016 inspection. WJE has noted similar sounds from other vertical lift bridge counterweight sheave assemblies. Based on WJE’s experience, this noise most likely emanates from the fit of the trunnion (shaft) with the sheave casting and is theorized to be caused by small relative movements at this fit. Although the fit is the likely source of the sounds, there was no fretting or other evidence of significant movement at the sheave and trunnion interfaces or at the dowels which are also used to secure the sheaves to the trunnions. See Photo M12, Appendix B. This issue is not expected to affect the reliable operation of the bridge. Although unlikely to be a significant long-term issue, it is recommended that the noises be monitored by maintenance and inspection personnel in the future. If there is a significant change in the behavior, then consideration should be given

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to providing an evaluation of the trunnion bearings by the manufacturer or a qualified expert. Typically, this test would be an ultra-low speed vibration study using accelerometers, where the tester can identify damage to the internal bearing components.

MAIN COUNTERWEIGHT WIRE ROPES

There are eighty (80) main counterweight ropes. Each rope is a 2-1/4” diameter fiber core rope with open spelter sockets at both ends of each rope. The counterweight ends of the ropes are pin connected to termination plates at the counterweight. The span ends of the ropes are pin connected to take-up rods at the lifting girder.

The inspection of the main counterweight ropes included a visual inspection of the ropes, connections, and guides. Rope stretch measurements, rope tension measurements, rope wear measurements, and socket pull-out measurements were also taken in addition to the visual inspection. The ropes were in fair condition with no broken wires or other significant issues.

The lubrication on the ropes was light at the time of the inspection. Light corrosion was noted along the length of the ropes, most notably where they contact the counterweight sheave grooves. At some of the lift girder connections the ropes were covered with light moss. See Photo M13, M14, and M15, Appendix

B. Note that sleeves installed on top of the counterweight side rope connections prevent a full inspection of the ropes, may prevent lubrication from reaching this critical connection, and may trap water. See Photo

M16, Appendix B. Maintenance personnel indicated that the ropes are typically lubricated twice per year.

This is an appropriate lubrication interval. When lubricating the ropes, it is recommended that the old lubricant be removed (to the extent possible) and that the entire surface of the ropes be lubricated, including under the installed sleeves at the counterweight connections and the sections of the ropes that do not pass over the sheaves such as near the counterweight and lift girder connections.

There was isolated corrosion on other components, such as at the fasteners near the wire rope guides at the lift girder take-up connections. The corrosion was minor at the time of inspection.

One measure of wire rope wear is through the length of the flat spots (commonly referred to as “wear flats”) which form on the crowns of the wires due to contact with the counterweight sheave during operation. The maximum measured wear flats were 9/16” long. Note that the maximum wear flat measurements were unchanged from the 2016 inspection. Wear flats can be used to approximate remaining strength of the wire rope if the classification of rope is known. Assuming the counterweight ropes are 6x19 fiber core ropes (per AREMA) and using wear charts published by Roebling, it is estimated that the counterweight ropes retain approximately 95% of their original strength, taking no deductions for corrosive effects.

Wire rope tensions were measured during the current inspection and are summarized in the Main

Counterweight Rope Tension Report in Appendix F. In the 2016 report, the rope tensions were presented and compared to the average of all rope tensions for each counterweight. For the current report, the rope tensions are compared to the average for each rope group and for each counterweight. The maximum and minimum tension variations from average for each rope group, and the coefficient of variation, are presented in Mechanical Table 5 in Appendix C.

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This change has been made to reflect the fact that rope tension adjustments are made to adjust load sharing within a given rope group; this convention is more common in the movable bridge industry. At the north counterweight, the tensions at five ropes were outside of 5% of their corners’ average, with the most significant deviation being -8.7% at NE-OB-10. At the south counterweight, the tensions at eleven ropes were outside of 5% of their corners’ average, with the most significant deviation being +8.4% at SE-IB-8.

These deviations represent small magnitudes compared to ropes’ capacity. No adjustments are recommended at this time.

The counterweight rope socket connections on the counterweight side were visually inspected and measured. From the visual inspection, there were no signs of recent relative movement of the ropes relative to the sockets. Socket pull-out measurements were taken at all ropes and were found to be less than 5/16 inch, which is a similar magnitude to measurements noted in the 2010 and 2016 reports. See

Photo M17, Appendix B.

As in previous inspections, counterweight rope stretch measurements were taken at the east and west end of each counterweight with the span in the seated position. The measurements were taken at a location marked by maintenance personnel, between structural steel at the underside of the tower and the hangers at the counterweights. The measurements are tabulated and graphed along with the previous reported measurements in in Mechanical Table 3 in Appendix C. The chart shows that the rate of stretch was greatest over the first two years of service, but the stretch has remained relatively constant since that time.

The noted stretch is not a significant concern for the reliable operation of the bridge at this time. Note that the stretch measurements may vary based on thermal expansion of components due to temperature changes. However, the effect of thermal expansion on the ropes and towers tend to offset each other and the impact may not be large. Although the effect of the expansion is not clear, it is recommended that the temperature be recorded at the time of future measurements for additional review of temperature effects if desired.

A significant reduction in the diameter of the ropes would be an indication of internal or external damage that would compromise the ropes. Wire rope diameters were measured at three locations on each rope and are presented in Mechanical Table 4 in Appendix C. The diameter measurements show that there has been no significant change in the rope diameters compared with measurements from the previous inspection.

AUXILIARY COUNTERWEIGHT SHEAVE ASSEMBLIES

The auxiliary counterweight sheave assemblies were in fair condition. The assemblies were visually inspected and observed during operation. The assembly at each corner consists of a rigidly mounted trunnion which supports an internally bushed sheave.

The sheave grooves were generally lightly worn with corrosion and light to moderate corrugations in the rope grooves. Corrugations will accelerate the wear of the ropes. At all sheaves, old lubricant had hardened around the edges of the grooves. Impacted corrosion was typically noted at the trunnion mounting for the sheaves. There was also corrosion of the tower structure near the auxiliary sheave mounting locations. See Photo M18, Appendix B.

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AUXILIARY COUNTERWEIGHT ROPES

There are eight (8) auxiliary counterweight ropes. All auxiliary counterweight ropes are stainless steel 1-

5/8” diameter right regular lay wire ropes of 6 x 19 classification with open spelter sockets at both ends.

The counterweight ends of the ropes are pin connected to termination plates at the auxiliary counterweight. The span ends are pin connected to the top chord near points U3 and U3’.

The ropes were in fair condition. There was minimal lubricant on the auxiliary counterweight ropes. Old and hardened lubricant was noted between the strands. The portions of the ropes near the span connections are partially painted. No wire breaks were noted, and no corrosion was visible, as they are stainless steel. See Photo M19, and Photo M20, Appendix B. Wire rope diameters were measured at three locations on each rope and are presented in Mechanical Table 4 in Appendix C. The diameter measurements, which were all within a typical oversize limit of +5%, show that there have been no significant changes in the rope diameters from a new condition.

The rope connections and guides were visually inspected with no significant issues noted. Rope stretch measurements were taken and are provided in Mechanical Table 3 in Appendix C.

LOWER SPAN LOCKS

The lower span locks were visually inspected and observed during multiple operations.

Lock Bars, Guides and Receivers

The guides and receivers were visually inspected and observed during multiple operations. The guides and receivers were in fair condition with the exception of the north receivers. The north receivers were damaged and were missing lower sections, rendering the north lower locks ineffective. See Photo M21 and M22, Appendix B.

The guide and receiver anchor bolts were in good condition with only light corrosion in spots. The lock bars were in fair condition with significant scoring in some locations, but the lock bars were well-lubricated at the time of the inspection and no corrective action is necessary.

Parallel Gear Reducers

The reducer housings were found with paint deterioration and surface corrosion in spots, particularly on the bolts at each reducer housing’s split line. See Photo M23, Appendix B. The parallel gear reducer inspection covers were removed to allow for visual inspection of the internal components. Corrosion also noted on the interior of the housing and on some of the gear teeth. See Photo M24, Appendix B. Light wear was noted on the reducer gear teeth with polishing across the face at the pitch line and near the tip on some teeth. At both reducers there were unusual patterns across the face and into the roots of the second reduction pinion teeth. These patterns may be from original fabrication. The teeth were found to be wearing in with no significant concerns. See Photo M25 and M26, Appendix B.

The oil levels at the reducers were appropriate. At both reducers, there was evidence of water ingress. An oil sample was taken from each parallel gear reducer for analysis. The analysis reports indicate the presence of water and metallic wear particles in the samples taken. Refer to Appendix D for fluid analysis reports.

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A crack was noted in the grout at the northeast corner below the south lower lock parallel shaft reducer.

See Photo M27, Appendix B.

Right-Angle Reducers

The right-angle reducers are coupled to the lower span lock motors and do not have a means for internal inspection. The right-angle reducer housings and mounting bolts, particularly at the north installation, were covered with surface corrosion. The reducers were designed with hex extension shaft at the undriven end for manual operation. The extension shafts of both north and south reducers were not usable due to severe corrosion and section loss. In addition, some impacted corrosion was noted at the shims located underneath the mounting feet. See Photos M28 and M29, Appendix B.

There are cracks in the grout under the pedestal near the south lock right-angle reducer. See Photo M28, Appendix B.

Open Gearing

The integrity of the lower lock open gears was fair with light apparent wear based on a visual inspection.

The gear teeth that are inaccessible with the locks engaged were found to be inadequately lubricated and exhibited surface corrosion. See Photo M30, Appendix B.

Couplings

The lower lock right angle reducer is coupling-connected to the parallel shaft reducer. There was paint deterioration and corrosion on the couplings and the spacers. It appeared that the couplings had not been lubricated recently since there was no evidence of coupling lubrication port plug removal. See Photo M31, Appendix B.

Bearings

The span lock bearings and their supports were visually inspected. The integrity of the bearings and their supports was good but there was light corrosion in spots, most notably at the supports and at fasteners.

See Photo M32, Appendix B.

The lubrication for the bearings was adequate. Bearing clearances were measured and are presented in

Mechanical Table 6 in Appendix C. An RC6 fit is the AREMA specified clearance for sliding bearings of this type. Clearance in excess of an RC9 fit is suitable basis for adjusting or replacing worn bushings. All of the bearing clearances were within an RC9 fit.

Linkages

The span lock linkages were visually inspected. The integrity of the linkages was good with only minor paint deterioration and corrosion in spots.

UPPER SPAN LOCKS

The upper span locks were in fair condition. The span locks were visually inspected and observed during operation. Operating pressures were recorded at each hydraulic power unit (HPU) during operation and

2022 Routine Inspection of Movable Bridge

Mechanical and Electrical Operating Systems

INSPECTION DATE: MARCH 7TH-11TH AND APRIL 8TH, 2022 12

fluid samples were taken for analysis. No issues were noted during operation of the span locks. Refer to

Mechanical Table 7 in Appendix C for HPU operating pressures and Appendix D for fluid analysis reports.

The main issue noted at the upper span locks was paint deterioration and surface corrosion in the areas of the lock bar, guides, hydraulic cylinders, fasteners, and within the cabinets that house the hydraulic power units. See Photos M33 and M34, Appendix B. There was no sign of oil leakage at any of the hydraulic systems. The lock bars were well-lubricated at the time of the inspection.

AIR BUFFERS

The air buffers are intended to absorb the inertial energy of the movable span if the span approached the fully open or fully seated positions without slowing. All air buffers were in fair condition externally and the buffer piston rods descended consistently under their own weight.

The lower buffers and areas of the upper buffers were in fair external condition. Noted issues included:

No pressure build-up was noted at any of the installed gages. This is an indication that the buffers are not generating pressure or that the gages were not functional.

Some portions of the buffers had light corrosion, most notably on some mounting bolts and lower flanges. See Photo M35, Appendix B.

The northwest lower buffer intake filter was not installed. See Photo M36, Appendix B.

Debris and moss collect on the gusset plats that surround the lower air buffers. See Photo M37, Appendix B. This condition will accelerate corrosion of the buffer assemblies.

LIVE LOAD SUPPORTS

The live load supports were in fair condition. The live load shoes had good contact with their strike plates.

The live load supports were generally well-painted with isolated areas of surface corrosion. Significant corrosion with minor section loss was noted at the anchor bolts for the north strike plates and south live load supports. See Photo M38, Appendix B. The south live load receiver bases collect standing water which will increase the rate of corrosion. See Photo M39, Appendix B.

CENTERING DEVICES

There is one centering device at each end of the bridge used to locate the lift span transversely when it is in the seated position. The centering devices were visually inspected and were in fair condition. There was no evidence of contact at the centering devices. At the south pier, it appears the span is possibly being located by the lock assembly instead of the centering device, as there was evidence of contact between the span-mounted lock receivers and the lock guide casting. See Photo M40, Appendix B.

At both centering devices, the paint has deteriorated and there was moderate corrosion at the centering device castings, mounting bolts, and anchor bolts. At the north centering device, light impacted corrosion was noted at the interface of the casting and the shims. Significant corrosion was also noted within the centering device base castings, though it does not appear to affect the integrity of the installations and there is limited access to address the corrosion. See Photo M41 and M42, Appendix B.

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Mechanical and Electrical Operating Systems

INSPECTION DATE: MARCH 7TH-11TH AND APRIL 8TH, 2022 13

SPAN GUIDES

The span guides were in fair condition. The guide rollers and rails were visually inspected and observed during operation. The contact area of the rollers and rails had light surface corrosion. The rollers all rotated freely by hand though the lubrication at some of the rollers was light. There was intermittent contact between the rollers and the guide rails during operation but no signs of significant loading though there were light fins on the rollers and rails from previous contact. See Photo M43 and M4, Appendix B.

MAIN COUNTERWEIGHT GUIDES

The main counterweight guide system was in fair condition. The counterweights were observed during multiple operations and no issues were noted throughout the length of travel. Old lube and debris had accumulated on the guides. Surface corrosion was noted in isolated locations on the guide supports though the integrity of the components was good.

AUXILIARY COUNTERWEIGHT GUIDES

The auxiliary counterweight guide system was in fair condition. The counterweights were visually observed during multiple operations and no issues were noted throughout the length of travel.

MITRE RAILS

The mitre rails were in good condition. The mitre rails were visually inspected and were observed during multiple operations. No issues were noted.

SPAN BALANCE

As part of this inspection the span balance was measured via the dynamic strain gage method. Strain gage data was recorded for three full bridge operations. The operations were run on the main motors and the bridge was run under normal operating speeds.

The following tables document the results of the balance testing. The tables present the seated imbalance and the average friction for each corner and each end of the lift span. The individual results from each test run are presented as well as the average results for all test runs.

NORTH TOWER RESULTS

TEST

Seated Imbalance Average Friction

NW

Corner

(lbs.)

NE

corner

(lbs.)

North

End

(lbs.)

NW

Corner

(lbs.)

NE

corner

(lbs.)

North

End

(lbs.)

Run 1 +5,716 +5,285 +11,001 2,642 3,034 5,676

Run 2 +5,607 +5,233 +10,840 2,717 3,144 5,861

Run 3 +5,526 +5,202 +10,729 2,764 3,251 6,015

Average +5,616 +5,240 +10,857 2,708 3,143 5,851

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INSPECTION DATE: MARCH 7TH-11TH AND APRIL 8TH, 2022 14

SOUTH TOWER RESULTS

Test

Seated Imbalance Average Friction

SW

Corner

(lbs.)

SE

corner

(lbs.)

South

End

(lbs.)

SW

Corner

(lbs.)

SE

corner

(lbs.)

South

End

(lbs.)

Run 1 +5,772 +5,752 +11,524 2,894 3,321 6,215

Run 2 +5,443 +5,452 +10,895 2,869 3,305 6,174

Run 3 +5,436 +5,614 +11,050 2,755 3,265 6,020

Average +5,550 +5,606 +11,156 2,839 3,297 6,136

Notes:

1. Imbalance and friction are presented as an equivalent force (lb.) at the counterweight rope connections.

2. Positive (+) Imbalance indicates span heavy (downward reaction). Negative (-) Imbalance indicates counterweight heavy (upward reaction).

The measured imbalance, with an average imbalance per corner of +5,503 lbs. was greater than the average per corner imbalance of 3,683 lbs. measured during the 2016 inspection. The reason for this change is unclear. The increase in imbalance is not a significant concern for the operation of the lift span, though consideration should be given to restoring seated imbalance to the desired condition based on the design of the machinery.

The strain gage recordings show that the G2-SW differential is not functioning properly to load share between the P1-SW pinions. Refer to the Span Balance Analysis Report in Appendix G. This was a known historical condition however the behavior load sharing was notably worse than in 2016.

VIBRATION TESTING

This inspection included vibration testing to determine displacements of the lift span and tower structures due to vibrations during rail traffic and during lift span operation. Records provided for comparison include similar testing that has been periodically performed dating back to 1984.

The results of the vibration testing are summarized in a report in Appendix H. Historical comparisons are challenging since detailed test procedures for all tests are not available, though it is notable that the results before 2000 appear to show very small displacement of the structures while testing after 2000 shows higher, more variable results.

Many of the current recordings show similar results to that shown in the 2010 and 2016 reports, however the calculated displacements at multiple events were higher than expected given the nature of the system, including the physical restraints on the lift span when it is in the seated position. It appears that some of the data had been negatively affected by non-vibratory loads such as impact loads and other accelerations.

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Mechanical and Electrical Operating Systems

INSPECTION DATE: MARCH 7TH-11TH AND APRIL 8TH, 2022 15

MECHANICAL CONCLUSIONS

The bridge mechanical systems were found to be in fair condition overall. The most significant mechanical issue noted during the inspection was damage at the lower span locks. The north span lock receivers had failed and no longer perform as designed. The locks will not restrain the bridge. This was discussed with maintenance at the time of the inspection and should be corrected in the near term.

The manual shaft extensions at the lower span lock right-angle reducers were not usable due to severe section loss from corrosion. Maintenance personnel noted that these reducers, along with the lower lock motors and couplings, are scheduled for near term replacement.

The span drive machinery was operated without issue during the inspection. Strain gage testing results indicate an increase in imbalance compared to the balance condition reported in 2016. Although the increased load is well within the capacity of the machinery, consideration should be given to adjusting the span balance to match desired balance condition. Through analysis of the strain gage balance data, it is apparent that the efficacy of the southwest corner differential has deteriorated since the 2016 inspection.

An issue with this differential assembly has been well documented by inspection personnel dating back to at least 2006. This condition should be monitored through periodic strain gage recordings to assess the load sharing of the southwest shaft over time. Consideration may be given to rehabilitating the assembly or, as a minimum, attempting to flush and or lubricate the seized bearings internal to the assembly.

Paint deterioration and surface corrosion are prevalent among all systems and should be addressed where noted to prolong the life of the machinery.

Lubrication was generally fair but with several issues that require maintenance attention. Oil analyses performed on the lower span lock parallel shaft reducers indicated the presence of water and metallic wear particles. These units should be flushed, provided with new oil, and monitored for contamination.

The span drive and span lock couplings are not regularly lubricated. These couplings should be flushed with lubricant yearly. The main and auxiliary counterweight ropes were insufficiently lubricated at the time of the inspection.

The motor and machinery brakes set without any mechanical time delay which will result in undesirable shock loading of the machinery under emergency stop conditions.