Large Scale Central

Geometry Car

Noticed this sitting on a siding in downtown while eating lunch today. A geometry car. I assume it is used to measure vertical and horizontal curves, deflections??? Just a guess!

Also, can anyone identify the engine coupled to it?


. . . And also super elevation, cross level, gauge, and a few other parameters that I no longer remember. Way back when I was a technical writer for N&W’s Computer Services Department, I made several trips on the N&W Plasser track geometry car to gather data for a manual on processing that car’s tapes in the computer center. The Plasser car was the prototype for the Bachmann HO model that doubled as a track cleaner in the mid-1980s.

Regards, David Meashey

P. S. Probably would be useful to mention that the Plasser car was self-propelled. It had two diesel engines. One engine was prime mover for the car. The other powered the data processing equipment for the track data collection system. I believe it used an HP minicomputer.

(Edited to add P.S.)

The engine (9999) is ex Amtrak F40ph…As for the car it could have been part of the old Conrail OCS fleet. I believe CSX acquired almost all of that fleet.

Thanks Dave and Rooster (

Is the geometry car a repurposed passenger car or specifically designed for the intended purpose?

Is there an Algebra car to go with it?..(

(I’ll be quiet now…(


Most of the geometry cars using passenger car bodies seem to be repurposed cars. The Plasser car I rode back in the day was especially built as a track geometry car. I think favor shifted to passenger cars because they ride better. Despite all the wheels under the Plasser car, only two axles were actually bearing the weight of the car, and it really rode rough.

Best, David Meashey


Although CSX doesn’t have a web page with their OCS roster (at least that I could find) NS does. I have molested this page many times over especially when I was working on my own office car train converting Aristo Heavyweights to my liking a few years ago (still not done).