Thanks for the list RTR12.
Here's few more to ad.
ABS-Automatic Block System
ALCO- American Locomotive company
Budd- Railroad car manufacturer
COFC-Container On Flat Car
CWR-Continuous Welded Rail
FM- Fairbanks Morse
GE- General Electric
LIMA- An American firm that manufactured railroad locomotive (1870's to 1950's)
Ma&Pa- Maryland and Pennsylvania railroad
RDC-Rail Diesel Car
USRA-United States Railroad Association