PS-4 Flatcars with piggy back trailers

Yes.

The Canadian Pacific was the first to pioneer PiggyBack service in December 1952....

Container stacks slowly replaced this technology in 1984 with the double stack container service...

I would say the PS4 trailers represent the '52 to '60's era...

Thank you

One ugly headed step child where the spline cars with truck bogies called Road Railers.

These were great for loading and unloading but a real curse trying to switch them at slow speeds... I got stuck behind a set of these a few years back in Fort wayne and my God they are a slow drag freight sometimes.

Here is a video of them going at a good clip on the main too....

From what I can find the PS4 flat car came into service in the late 40s.

The trailer-on-flatcar, or TOFC, concept appeared at least as early as 1926 when the most unlikely of railroads began experimenting with the concept; the Chicago, North Shore & Milwaukee , a large interurban system which served its namesake cities.   The North Shore Line was followed by the innovative Chicago Great Western in 1936, the first standard railroad to adopt TOFC in 1936.

Similarly, COFC, or container-on-flatcar service dates back to at least 1928 when the Pennsylvania Railroad tested the idea using specialized 40-foot flatcars which carried five containers.  It was discontinued in 1950.  As the 1950s gave way to the 1960s TOFC, also known  as "piggyback" (since the truck trailers "piggybacked" their trip on flatcars), began to gain momentum with many Class Is using the service in one form or another.  Some truly embraced the idea and the PRR was again at the forefront with its TrucTrain service.

http://www.american-rails.com/flatcars.html

http://www.trainweb.org/twerhs/northshore.html

Thank you for the information.

Your Welcome. also go to below link. Erik did a great job and there is a lot of good information. 

https://ogrforum.com/t...yback-project?page=1