Pat,
Yes, it seems that regulations allowed the older dark navy blue uniform to be worn inside the Reich but the light blue uniform was supposed to be worn outside in places like Poland and Holland. Railway Police authority went wherever the tracks ran so when German trains were on track outside Germany the BZP were there. They went into all the occupied countries to operate and maintain the railroads.
Here is a closeup of the collar tabs. Notice that there are two lines of piping as this grey Nebenfarbe indicates this fellow is a Reserve-Policeman. That basically means he is on a different pay scale and is not a permanent civil service type employee.
George
