PRR structures color scheme

I am an Italian railfan who is planning to build a PRR prototypical layout set in the fifties.
I need some information on the color scheme the PRR used for its structures during that age. In particular, I have understood there were two main possibilities for wooden structures:
1. PRR buff (walls), flat brown (trim) and red (windows)
2. PRR buff (walls), green (trim) and red (windows)

I have the following questions for you:
1. I bought “Polly Scale Railroad Acrylics - PRR Buff” but I found it too dark if compared to the original light yellow color found in several pictures. Please could someone tell me the right mix (PRR buff – white) I should use to get the original effect?
2.Please could someone also let me know the specifications for the other colors (green, brown and red)?

Many thanks in advance for your help.
Marco

In the 50s, PRR was still recovering from deferred maintenance since the start of World War Two, so the colors were probably faded quite a bit. Use the colors you mentioned, and weather them. Chalk weathering will turn them lighter and more "faded".