Freight Car Friday – Spine Cars

4 04 2014

Articulated “spine cars” are a common sight on North American mainlines today as they carry trailers and containers in priority intermodal trains. While their use has exploded in recent decades, the history of this “bare bones” car goes back much further.

skeleton car

The skeleton log car was more efficient in mountain operations.

The earliest spine cars weren’t used to haul trailers or containers. In fact, they were about as far from the high-speed freight intermodal market as you could get! Used by logging companies as early as the late Nineteenth Century, the basic spine car offered a vehicle with a minimum light weight and easy unloading of large logs.

Simple to build, these cars were not much more than trucks and a center frame or “spine.” Cross beams over the truck helped support the log loads. Stacked and chained down at the logging camp, once the logs arrived at the mill unloading was a simple matter of unbuckling the chains and tipping or pushing the logs off and into the mill pond.

front runner

The Front Runner took minimal design to the limits – or maybe just a bit too far beyond them. One example was literally plucked from the scrap line for preservation at the Museum of Transportation in St Louis.

Eliminating the cost, weight and maintenance of a flatcar deck made sense in this service. It would be many decades however before the idea found a practical use in common carrier rail lines.

The first uses of spine cars in intermodal service began in the late 1960s with projects like the Clejan car on the New Haven and Southern Pacific and the better-known Flexi-Van cars on the New York Central and several other railroads. Like the logging spine cars, the basic premise behind these designs was to reduce the weight and cost, and inefficiencies of the flatcars currently used in Trailer on Flatcar service.


A 5-unit spine car loaded with 53′ domestic containers is a contemporary staple. This car can also carry trailers.

These pioneering spine cars were similar in length to the longer flatcars then in service for hauling trailers, 75 feet. Of course you couldn’t load these cars the same way you’d load a conventional flatcar, and therein lay the real drawback to the designs. The FlexiVan car used a turntable on the spine to pivot the container load so that no special cranes were needed. But this had its own set of problems from extra maintenance and complexity on the cars to a need for empty chassis at each terminal. For the efficiencies of the cars to be realized, railroads would also have to redesign the terminals and purchase new equipment to load and unload the spines.

As intermodal trains continued to evolve into longer-haul services from fewer dedicated hubs in the 1970s, the climate improved for alternatives to the flatcar and conventional “circus style” loading. In the 1980s, the first new spine car to have a major impact was the “Front Runner” – a single unit car whose construction took minimization to the extreme. The central spine had two platforms attached at one end to support the trailer’s wheels. It rode on two axles with only 28″ wheels to lower the total height. The cars were light – too light – and were prone to derailments, especially when running empty and mixed in with heavier, traditional equipment.

trash spine

Although normally thought of for traditional intermodal containers and trailers, specialized spine cars can be found in waste container service as well.

The advantages of this reduced design were apparent however and railroads, car builders and Trailer Train all partnered to bring new designs to the rails. By the end of the 1980s, the five-unit articulated spine car emerged as the new standard. Articulation allowed use of conventional trucks while further reducing weight and coupler slack in a train. While some early spine cars were trailer only or container only, dual-capacity cars soon emerged for greater flexibility and fleet utilization.

Since then, the overall form of these cars has changed little. The most consistent change was an ever-increasing length of the individual cars to accommodate longer trailers. Today both three and five-unit cars are common. Together with the double-stack container well cars, these platforms form the “backbone” of the North American intermodal fleet.



2 responses

4 04 2014
Andrew Falconer

You have to make the Traditional O Gauge ARC-5 Spine Cars used for intermodal trailers as 5-unit cars in the various ATSF Santa Fe paint schemes. The Santa Fe used various combinations of white, yellow, and blue paint and graphics on the intermodal trailer spine cars. There must be at least 4 different Santa Fe paint schemes for the ATSF spine cars.

Thank you.

6 04 2014
Conductor Andrew

Reblogged this on theredcaboose1.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: