Integrated Railmotive Systems Inc.

Excellence in Engineering


    Recent increases in AAR maximum wheel and line capacity problems with unit coal trains on some western railroads suggested to Railmotive the possibility that a new six wheel truck could be developed to increase car capacity.  Such a truck would have to be less expensive to manufacture and easier to maintain than existing designs. We hoped to apply the techniques used in our lightweight Iron Highway four-wheel truck design to bring these requirements about.
     In particular, the large cast steel truck frame might be lightened considerably if pedestals were eliminated and radial axle guidance used. The heavy cast steel bolster could be eliminated by a bolsterless design, where vertical load was transmitted directly up into the car sides with the lateral structural members serving only to stabilize the position of the frames. Provision is also made for easy removal of the center axle from the truck and of the truck itself from the car.  Finally, to the extent possible all moving parts are guided by rubber-in-shear, either via rubber bushings or chevron mounts, so that mechanical wear will be minimized. The truck shown in exhibit 19-1 was designed with these concepts in mind.

A pair of these trucks would have a Gross Rail Load capacity of 429,000# and could be used under articulated intermodal cars where each platform could have an equivalent GRL of 215,500#.  A five packer multi-platform car with this arrangement would be able to handle two 85,000# containers in each well and the center platforms could weigh as much as 45,000# minus the weight of one truck. The truck weight is conservatively estimated as 15,500# so subtracting that amount from the 45,000# limit would leave 29,500# as the design max weight for a center well platform and this is well within the range of existing carbuilding technology.
    The first use proposed for the new truck was, however, a high capacity gondola car, which could be employed to increase the throughput on coal routes where railroads found themselves nearing full capacity with existing car technology. This concept was proposed by Railmotive to a major carbuilder, who funded a design study that fleshed out the concept with enough detail to make preliminary estimates of cost, weight and marketability.  In discussing the concept with a major coal consumer, however, we determined that the customer did not plan to build any additional coal burning capacity in the near future, and did not feel that the cost savings offered would justify replacing existing cars with many years of life left. At about this time, the economic recession was beginning, and the carbuilder who had an option on the design, allowed it to lapse and remain the property of Integrated Railmotive Systems Inc.