From the 1937 Official Railway Equipment Register:

Number
Series
Car Type MCB
Designation
Number
of Cars
Inside
Length
Outside
Length
1875-1899 Refrigerator,steel underframe RS 12 33′-0″ 41′-5″
1000-1499 Coal, hopper bottom GA 123 36′-0″ 39′-0″
1500-1599 Ballast MWB 99 37′-9″ 41′-0″
1600-1704 Coal, hopper bottom GA 38 36′-0″ 39′-0″
1900-1930 Stock, single deck SM 28 36′-0″ 38′-0″
1940-1999 Stock, single deck SM 30 35′-4″ 37′-6″
2300-2375 Flat, steel underframe FM 75 36′-0″ 36′-10″
2700-2799 Flat, steel FM 98 40′-0″ 41′-2″
3000-3059 Coal, steel underframe GX 38 34′-4″ 36′-10″
7000-7499 Box, steel underframe XM 484 36′-0″ 38′-1″
7999 Box, steel underframe XM 1 40′-6″ 42′-9″
8000-8299 Box, steel underframe XM 297 40′-6″ 42′-3″
9000-9199 Auto, box, steel underframe XAB 199 40′-6″ 42′-3″
10000-10099 Coal, steel hopper HM 99 30′-0″ 31′-6″

From the 1953 Official Railway Equipment Register:

Number
Series
Car Type AAR
Designation
Number
of Cars
Inside
Length
Outside
Length
1500-1599 Ballast WB 36 37′-9″ 41′-0″
1907,1920 Stock, single deck SM 2 36′-0″ 38′-0″
2600-2645 Flat, steel underframe FM 9 36′-0″ 36′-10″
2700-2799 Flat, steel FM 30 40′-0″ 41′-2″
4000-4034 Gondola, SUF,
fixed ends, wood floor
GB 30 36′-0″ 41′-2″
4100-4108 Gondola, SUF,
fixed ends, wood floor
GB 8 34′-4″ 36′-10″
4500-4505 Gondola, SUF,
fixed ends, wood floor
GB 5 38′-0″ 41′-2″
6000-6088 Box, steel underframe XM 86 40′-6″ 42′-3″
7208, 7324 Box, steel underframe XM 2 36′-0″ 38′-1″
7999 Box, steel underframe XM 1 40′-6″ 42′-9″
8000-8299 Box, steel underframe XM 135 40′-6″ 42′-3″
9000-9199 Box, steel underframe XM 42 40′-6″ 42′-3″
10000-10099 Coal, steel hopper HM 15 30′-0″ 31′-6″

From 1961 Official Railway Equipment Register:

Number
Series
Car Type AAR
Designation
Number
of Cars
Inside
Length
Outside
Length
100-199 Box, Steel XM 100 40’6” 41’10”
200-299 Box, Steel XM 100 40’6” 41’10”
300-450 Box, Steel XM 147 40’6” 41’10”
427, 440, 448 Box, Steel XM 3 40’6” 41’10”
500-514 Covered Hopper, Steel LO 15 29’3” 34’3”
750-764 Hopper, Steel HM 15 34′ 35′
1000-1024 Gondola, Steel, Fixed Ends GS 25 52’6” 54’6”
2700-2799 Flat, steel FM 25 40′-0″ 41′-2″
4000-4034 Gondola, SUF,
fixed ends, wood floor
GB 16 36′-0″ 41′-2″
4105,4106 Gondola, SUF,
fixed ends, wood floor
GB 2 34′-4″ 36′-10″
4500-4509 Gondola, SUF,
fixed ends, wood floor
GB 8 38′-0″ 41′-2″
6000-6088 Box, steel underframe XM 15 40′-6″ 42′-3″
7999 Box, steel underframe XM 1 40′-6″ 42′-9″
8000-8299 Box, steel underframe XM 16 40′-6″ 42′-3″
9000-9199 Box, steel underframe XM 4 40′-6″ 42′-3″
427, 440, 448 – Not equipped with permanent lading tie anchors.