2011 Tie_specs[1][1].doc

Specification For New Timber Cross-ties.

New Cross ties shall be manufactured of mixed hardwoods of the order consisting of Oak, Beech, Birch, Cherries and Hard Maples.

Anti-splitting end plates shall be selectively applied and shall be galvanized steel plate gang nail type.

(a) Design. .

Cross ties shall be 8 feet 6 inches in length and shall be 6 inches by 8 inches in cross section with a maximum of 1 inch of wane allowed in the rail bearing areas. A maximum of 30 percent of the order may be 6 inches by 7 inches in cross section with no wane allowed in the rail bearing areas.

The lengths and thicknesses specified are minimum dimensions. Ties over one inch wider or thicker, or over three inches longer, at any point, than the dimensions specified above, will be rejected.

Anti-splitting gang nail end plates shall be 5 inches by 6 inches. It shall be manufactured from 18 gauge galvanized steel plate with teeth extending at least 3/8 inches beyond surface of plate. Plates shall be installed centered on end of tie and fully driven with no evidence of excessive bending or mashing of teeth.

(b) Manufacture. Cross ties shall be manufactured from sound, live timber and must be free from any defects that may impair their strength or durability as cross ties as further described in this section.

All ties shall be straight, well sawn on four sides, cut square at the ends, have top and bottom parallel and have bark completely removed. A tie will be considered straight when a straight line along the top, from the middle of one end to the middle of the other end, is entirely within the tie and when a straight line along a side, from the middle of one end to the middle of the other end, is everywhere more than 2 inches from the top and bottom of the tie. The top and bottom will be considered parallel when any difference in the thickness at the sides and ends is less than or equal to 1/2 inch. Cross ties shall be free from the following defects:

1.

Decay - Ties that show decay of any nature and ties that show stain from being left in the log too long will be rejected. "Blue stain" is not decay and is permissible in any wood.

2.

Holes - Ties will be rejected if a large hole, or numerous holes with the net effect of a large hole, is present. A large hole is one exceeding 1/2 inch in diameter and 3 inches deep within the RBA*, or more than one-fourth the width of the surface on which it appears and 3 inches deep outside the RBA*.

3.

Knots - Ties with a large knot, or numerous knots with the net effect of a large knot within the RBA* will be rejected. A large knot is one whose average diameter is greater than one-fourth the width of the surface on which it appears.

*RBA -

Rail Bearing Area - the area of the top of tie between 20 inches and 40 inches from its middle.

4.

Shake - Shake greater than one-third the width of the tie will be cause for rejection of the tie.

5.

Split - A tie will be rejected if a split exceeds 5 inches long or 1/2 inch wide.

6.

Slanting Grain - A tie will be rejected if a slant in grain in excess of 1:15 is present, except in the case of woods with interlocking grain.

7.

Wane - Excessive wane will be cause for rejection of the tie.

(c) Seasoning. Cross ties shall be air seasoned prior to treatment. Ties shall be stacked for seasoning in accordance with AREMA Specifications, Chapter 3, Part 5, Section 6. Seasoning shall continue for at least 12 months and no more than 18 months.

In the absence of air seasoned cross ties, the Vapor or Boulton drying process may be used with the permission of MDOT, or their designee. If the Vapor or Boulton process is used, conditioning should continue until moisture removal rate indicates a percent moisture retained equal to a 12 month air dried cross tie, but not less than 45 percent by weight.

A minimum of 20 borer cores per treatment charge shall be taken of seasoned ties to determine that adequate drying has taken place so that ties may be satisfactorily penetrated with preservative.

On air seasoned ties the borer cores shall be taken mid-way between the ends and mid-way between the top and bottom faces of the tie. Three (3) inch borer cores shall be taken to determine moisture content.

Prior to seasoning, selected ties shall have anti-splitting devices applied at each end of the tie.

(d) Treatment. Prior to treatment anti-splitting plates must be checked to ensure that plates are firmly imbedded in the tie. If plates are found to be loose or not flush against the end of the tie, plate shall be firmly pressed against the tie before treatment begins.

Cross tie treatment shall be to retention of seven pounds or to refusal of 60/40 creosote coal tar solution per cubic foot of timber in accordance with the latest AREMA Manual, Chapter 3, Parts 7, 8, & 9.

A minimum of 20 borings shall be taken per charge after treatment to determine proper penetration. Verified test results from borings shall be provided to MaineDOT project manager to assure proper penetration.

ADDITIONAL SHIPPING INFO:

Shipped in bundles of 25, via rail car to Brunswick Maine.