October 20, 1992

CIRCULAR LETTER
(C-7911)
CC-201.S92

SUBJECT: Recommended Practice for Freight Cars With 286,000 lb. Gross Rail Load

TO: Members and Private Car Owners

File:AC-1928
CRB-932
(C-7911)

The Car Engineering Committee has approved a Recommended Practice for cars designed to carry a 286,000 lb. gross rail load. The attached proposal specifies that the car body be designed for 286,000 lbs. and the standard design loads of M-1001 be increased by a factor of 1.09 over those specified for a 263,000 lb. gross rail load car. In addition, the proposal specifies fitted backing rings and axles on new and rebuilt cars.

In accordance with the provisions of AAR Standard S-050, the views of interested parties on this proposal are hereby solicited. Responses should be directed to the Secretary-Mechanical Division, and should reach this office within 30 days of the date of this circular. All comments received by that date will be considered in finalizing the Recommended Practice.

Sincerely,

Leavitt A. Peterson

Association of American Railroads
Mechanical Division
Manual of Standards and Recommended Practices

SPECIFICATION FOR 286,000 LB. GROSS WEIGHT RAIL CARS

Recommended Practice

RP - 259 - 92
Adopted 1992

1.0 General

Freight cars built under this specification are subject to all normal FRA regulations. Unless specifically addressed in this specification, all appropriate AAR Standards must be met in the design, building and operation of cars with a gross rail load of 286,000 lbs.

2.0 Scope

The following specifications outline the recommended requirements for operation in interchange by agreement for cars with a gross rail load of 286,000 lbs. These guidelines are not considered mandatory.

3.0 Definition

This specification applies to 4-axle freight cars designed to carry a gross rail load of 286,000 lbs.

4.0 Guidelines

4.1 Carbody

Design of the car body (including the sides, ends and underframe unless otherwise noted), shall be based on a gross rail of 286,000 pounds. Where standard design loads are specified for 100-ton cars in AAR Specification M-1001, those loads multiplied by the factor 1.09 shall be applicable to the subject cars.

4.2 Brake System

4.2.1

Brake Systems must meet the braking ratios of S-401.

4.3.1 Bearings

4.3.1.1

The standard bearing size of 6½" X 12" will be used.

4.3.2

A fitted backing ring design on a fitted axle is required for cars built new or rebuilt. Bearings on existing cars used for 286,000 lbs. GRL must have cap screws retroqued in accordance with AAR approved procedures outlines in the Wheel and Axle Manual.

4.4 Wheels

Wheels are to be 36 inch, curved-plate, grade C.

4.5 Draft System

4.5.1

All draft components must be Grade E steel.

4.5.2

Draft Gears must conform with AAR M-901E, M-901G, or M-901H latest revision.

4.6 Springs:

Springs are AAR Standard D-5, 3 11/16" travel or D-7, 4¼" travel in accordance with AAR Specification M-114, latest revision. Solid spring capacity per group must be 1½ times static sprung loading at full rail loading.

4.7 Trucks

Trucks shall be standard 3-piece cast trucks. Roller bearings shall be employed. Design of the trucks generally should follow S-300, latest issue based on 6½" X 12" journal size, 5'10" wheelbase, and 36" diameter wheels. Designers may elect to upgrade the material or geometrical design to accumulate the higher gross rail load for improved reliability and longevity. However, all the limiting nominal design dimensions for trucks contained in S-302 shall be adhered to. Castings shall meet the requirements of M-202, M-203 and M-210.