Appendix 5. - Specifications - IFB PUR1-24-1048 Timber Switch Ties.pdf
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- Attached to
- IFB PUR1-24-1048 - MTA Timber Switch Ties
- Solicitation number
- BPM040526
- Issued by
- Maryland
About this file
This document is the Specifications Appendix for Invitation for Bids (IFB) PUR1-24-1048, issued by the Maryland Department of Transportation Maryland Transit Administration (MDOT MTA) for the procurement of new timber switch ties. The specification covers the manufacturing, treatment, inspection, and shipment requirements for 22-foot timber switch ties to be used in MDOT MTA's Light Rail system. The ties must meet AREMA and AWPA standards and be made of red or white oak, with specific requirements for size, straightness, seasoning, and quality. The ties must be pressure treated with a 60/40 creosote/coal tar solution, with a minimum retention of 8 pounds per cubic foot. Anti-splitting devices in the form of nail plates must be applied prior to treatment, and the treated ties must be branded with the wood type, year of treatment, supplier information, and MTA's identity.
The IFB is for a one-time purchase of an unspecified quantity of the timber switch ties. Detailed instructions are provided for the manufacturing, treatment, and delivery of the ties, including notification to the Administration when the treated ties are ready for shipment. No information is provided regarding pricing, set-asides, funding sources, or contract term and renewal options.
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TIMBER SWITCH TIES IFB PUR1-24-1048
Switch Ties 22 ft Page 1 of 3
Appendix 5. - Specifications
TIMBER SWITCH TIES
1.1 DESCRIPTION
A. This Appendix specifies the manufacture, treatment, inspection, and shipment of new timber switch ties.
1.2 REFERENCE STANDARDS:
A. Timber switch ties shall be manufactured, designed, handled, treated, delivered, and inspected in accordance with the latest edition of the American Railway Engineering and Maintenance of Way Association (AREMA) and the American Wood Preserver’s Association (AWPA) standards, except where these documents are amended by these Specifications.
2.1 GENERAL REQUIREMENTS FOR TIMBER TIES
A. Timber ties shall be new and conform to the requirements of AREMA manual, Volume 1, Chapter 30, except as modified herein.
B. Wood Species – Red or White Oak
C. Sawing – All timber ties shall be straight sawed top, bottom, and sides, cut square at the end, and the bark entirely removed. A tie will not be considered well – sawn where its surfaces are cut into score marks more than ½ inch deep, or where its surfaces are not even.
D. Straightness – A tie will be considered straight when a straight line from a point at one end to a corresponding point on the other end is no more than 1-1/2 inches from the surface at all points.
E. Sizing – Tie dimensions for each designated size shall not be averaged.
F. Seasoning – All ties shall be air dried to an oven dry moisture content of 50 percent or less prior to preservative treatment.
2.2 SWITCH TIMBER TIES
A. Meet AREMA specifications for Switch timber ties, except as modified herein.
B. Size – 7 inches thick by 9 inches wide
C. Length – 22 feet
Switch Ties 22 ft Page 2 of 3
2.3 GENERAL QUALITY
A. All ties shall be free from any defects that may impair their strength or durability such as decay, large shakes, slanting grain, or large or numerous holes or knots.
1. Decay: Decay is the disintegration of the wood substance due to the action of wood destroying fungi. “Blue stain” is not considered to be decay and is permissible in any wood.
2. Holes: A large hole is one with more than ½ inch diameter and 3 inches deep within, or more than one-fourth the width of the surface on which it appears. Numerous holes are any number equaling a large hole in damaging effect and are not permitted.
3. Knots: A large knot is one having an average diameter more than one-third the width of the rail bearing surface area on which it appears. Numerous knots are any number equaling a large knot in damaging effect and are not permitted. Knots located outside of the rail bearing area of the tie are permitted.
4. Shakes: A shake is a separation along the grain, most of which occurs between the rings of annual growth. The length of a shake cannot exceed one-third of the width of the tie and cannot be closer than one inch to any surface.
5. Split: A split is a separation of the wood extending from one surface to an opposite or adjacent surface. In unseasoned ties, a split no more than 1/8 inch wide and 4 inches long is acceptable. End splits and shrinkage cracks that do not impair the fastening bearing area or strength of the tie will be permitted.
6. Cross Grain: Ties with excessive cross grain are not permitted.
B. Tie members shall be straight grained. Members shall be cut without heart center or sapwood. Small drying cracks or splits are permitted.
2.4 ANTI-SPLITTING DEVICES
A. Nail plates shall be as specified in AREMA Volume 1, Chapter 30, Article
3.1.6 and as specified herein.
B. Nail plates shall be at least 18-gauge galvanized steel conforming to ASTM A446 Grade 4, and the galvanizing conforming to ASTM A525.
C. Nail plates for timber ties shall be 5 to 7 inches deep by 6 to 8 inches wide.
2.5 PRESERVATION TREATMENT
A. All ties shall be pressure treated by the empty cell process with a 60/40 creosote/coal tar solution (Grade C) in accordance with AREMA “Specifications for Preservatives and Specifications for Treatment” and
AWPA C-6.
Switch Ties 22 ft Page 3 of 3
B. The retention of the treatment solution shall be a minimum of 8 pounds per cubic foot.
3.1 ANTI-SPLITTING DEVICES
A. At the start of the seasoning period, nail plates shall be applied to both ends of each tie in accordance with AREMA Volume 1 Chapter 30, “Specifications for Devices to Control the Splitting of Wood Ties”, Paragraph 3.1.7.4 b.
B. Application:
1. Gang nail plates shall be centered, plus or minus ½ inch on the timber ends.
2. Gang nail plates shall be driven flush with the ends of the ties.
3. If an excess of 5 percent of the nails fail to penetrate fully, the plate shall be removed and a new plate shall be installed.
3.2 PRESERVATIVE TREATMENT
A. All ties shall have all bark, dirt, saw-grease, mud, and other materials removed from the surface so not to hinder the penetration of the preservative. Apply the preservative in accordance with AREMA Manual, Volume 1, Chapter 30, Section 3.9, and the American Wood Preserver’s Association Standards C6, as applicable.
B. Notify the Administration when the treated ties are ready for shipment.
Each treated tie shall be stamped for quality control indicating compliance with these specifications.
3.3 MACHINING
A. All machining of timber ties shall be performed prior to preservative treatment.
B. Boring shall be performed in accordance with AREMA Manual, Volume 1, Chapter 30, Paragraph 3.1.4.3.
C. Adzing (Dapping) shall be performed prior to preservative treatment and to the dimensions shown on the drawing in the Appendix. Tolerances shall be as required to assure proper form, fit, and function.
D. Ties shall be branded on one end in accordance with AREMA, Chapter 30, Article 3.1.4.5 and shall show the following information:
1. Type of Wood
2. Year of Preservative Treatment
3. Identity of supplier and plant
4. Identity of tie owner (MTA).
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