Source: adapted from T. Prince (2001) “Towards an international intermodal network”, American Shipper, November.
An important shift in the composition of the North American intermodal rail fleet took place in the 1990s with the move away from piggybacking (Trailer on Flat Car; TOFC) towards Containers on Flat Car (COFC). The development of long-distance corridors linking major port gateways such as Los Angeles / Long Beach to inland destinations incited the setting of double-stacked unit train services. TOFC services that once dominated have become marginal. This is related to more efficient use of rail assets enabled by double-stacked services, as well as trucking companies’ commitment to integrate their drayage services with long-distance intermodal rail services. Also, most well cars can accommodate 53-foot domestic containers, undermining the need for piggybacking. What used to be carried as TOFC is now carried as COFC.