This picture shows the re-railer in position to do its job. As you can see by the scratches, it is well used. We have re-railed our Hudson (wet weight = 1500 lbs.) a few times, and our cars ,and everyone else' cars many times. With 1 exception, when we had all 14 wheels on the ground, we were able to drive the engine back on the track under its own power. Cars are a piece of cake.
This picture shows the side view. The blocks are the same height as the rail so that the re-railer is supported by the ties and just rests on top of the rail. The angle is such that the other end, the one without the blocks, will also rest on the ties. The length is arbitrary and can be made to suit. The particular unit is 15" overall with the support blocks being 6".
This shot is of the bottom of the unit. Notice the two thin strips of metal on the right hand side. They are spaced to just fit inside the rail head. This give some lateral stability. The slots on the left hand side are cut wide enough to clear the foot of each rail so the unit is supported by the ties and not the rail. The spacing of the slots is determined by your track gauge.
If you have any questions or comments your can reach me at smithh@www.livesteamclubs.com.