Andrews 50-ton freight truck

An interim, cost saving truck accepted by the ARA and AAR, was designed by the Andrews Company, and also by Vulcan, which entailed a cast steel frame that reused the original journal boxes and axle sets that could then be bolted into the cast frame, discarding the strap iron of the arch-bar, yet allowed the journal boxes and axles to be easily dropped out without disassembling the entire truck.  These remained in production into the 1930’s and remained in service on many railroads for many years.

The earlier trucks were more or less 'journal boxes’ bolted together by an arrangement of strap iron to form what generally became known as the ‘arch-bar’ truck, and was used by almost all railroads.  These had the problem of coming unbolted at speed resulting in numerous train wrecks, and as a result, in 1937, was out-lawed by the AAR for any interchange service.  The difficulty with the integral cast side frame was that to change out wheels the entire truck had to be dismantled, whereas the arch-bar only had to unbolt and drop out the journal boxes to remove axles.