Today’s intermodal equipment takes many forms. For decades however, there was only one standard – the flatcar.
The origins of TOFC, or Trailer On FlatCar, service began in the Nineteenth Century. It wasn’t until the mid-1950s however that the service began to grow into the important traffic source we know today. The common term “Piggyback” as applied to this service actually originated with Pullman Standard advertising in 1954.
In the first decades of TOFC, two types of flatcars emerged. New cars dedicated for hauling trailers were built, most to a length of 75′. The cars were long enough to hold a pair of 35′ trailers. While the cars were long compared to conventional freight cars of the era, they were no longer than passenger equipment and few railroads had any issues with interchange of the cars in most traffic corridors.
By carrying two of what were at the time the largest trailers on the road, the 75′ flatcar offered a more efficient car weight / capacity ratio. And the new dedicated cars were designed for much more efficient loading and unloading, using collapsible “fifth wheel” hitches. The rub rails along the sides of the cars could be used for additional tie-downs and also to help prevent a trailer from being backed over the side when loading.
As the service took off, new cars could not be purchased fast enough. There were also roads that could not afford the new equipment. This led to a movement to convert older, standard designs for TOFC service. Most common were the conversion of 50′ cars which could hold two smaller 25′ trailers or a single larger trailer. While less efficient in service than the modern cars, these were cheaper and faster to put in service and had the advantage of equally quick to convert back into standard flatcars if demands changed again.
The balancing act between efficiency and production costs would continue to define TOFC flatcars over the coming decades. One of the biggest forces driving a constant change in the cars was the trailers themselves. As trailers grew ever larger, the flatcar also had to expand to keep pace. 40′ trailers pushed the development of an 85′ car. No sooner were these starting to be produced than trailers grew to 45′ and the 89′ car became the new standard intermodal flatcar.
The 89′ Flatcar became a versatile platform for many different types of loads. For TOFC service, most could haul a pair of trailers up to 45′ in length each (each overhung the end of the flatcar by a few inches – accommodated by a longer coupler shank.) Others were equipped with hitches for three smaller 28′ “pup” trailers favored by the LTL (Less than Truck Load) and parcel carriers. In addition to trailers, many flats were designed for the option of carrying containers as well. We’ll talk about these in a future blog.
During the reign of the 89′ flat, many intermodals switched from the old “circus style” loading to using large cranes or special lifts to load the trailers. The 1980s saw the removal of the bridge plates from the ends of the cars which had allowed the trailers to be moved across the gaps during loading.
While the 89′ flatcar was the most common in this era, shorter “conversions” were also still found. Like the early days, these were done to fill a rapidly growing need at low cost using existing equipment. Most telling were conversions made not from flatcars, but older boxcars. The rise in TOFC traffic was seen as conventional boxcar traffic was in decline. Several railroads sent unused boxcars into their shops, cut them down and converted them into dedicated TOFC flats. To reduce weight further, and with trailers now being loaded by crane, many of these cars only had a partial floor – another sign of changes to come.
While the railroads enjoyed a fleet of tens of thousands of 89′ flatcars, the trucking company continued to push for even larger trailers. When 48′ and then 53′ trailers arrived on the scene, the utility of the 89′ flatcar had been exceeded. Extending the length of the car was no longer a practical option. Single-trailer loading offered not only a very poor weight efficiency, but add fuel costs as the large open spaces between trucks created additional wind drag.
In order to extend the life of many flatcars, companies like Trailer Train and Florida East Coast began joining a pair of cars with a drawbar. With a single trailer up to 57′ in length on each, a third could be placed across the gap. Some of Trailer Trains earlier “Long Runner” conversions also required widening the deck and sides to accommodate that center trailer’s bogie as it slid across the deck through curves.
By the early 1990s however, the need for non-conventional equipment for handling trailers had become obvious. Rather than adapting for intermodal use, many 89′ cars were modified for hauling other loads – everything from heavy equipment to pipe, to auto frames and rail. Articulated platforms offered much greater efficiency in operation than the traditional flatcar. While you will still see one occasionally in an intermodal train, the presence of a true flatcar is becoming quite a rarity.