Tank car buffer cars

[Brakie]

A agreement between the FRA and the railroads allows one buffer car between engine and a buffer car is needed as the last car on the rear of the train on unit tank trains of crude oil.

Its not an "agreement", its the CFR hazmat placement rules.

According to what I read and was told by a retired CSX and NS conductor the FRA wanted 3 buffers behind the engines and two buffers on the end of the train. The railroads and FRA came to a agreement one buffer would be ok..