I found a copy of a SRY TT that Marvin Black copied and sent me probably early 2000's.
It does not mention the year but as I recall Marvin stated it was in the 1940's
It has a few codes:
I can probably scan it into a PDF if anyone is interested.
A few codes include:
G Coaling station (chute bin,platform tipple)
H stock pen
P hospital at that location
R engines are coaled from cars at the location
Y "Y" track at location
D passenger trains stop at flag