These were the most typical passenger diesel locomotive models used by the private railroads, prior to the formation of Amtrak. An "A" or a "B" in the model designation usually identified an "A-unit" or a "B-unit". An A-unit had a cab, and was required to be the leading locomotive if there were multiple units. And a B-unit did not have a cab, and could only be behind a leading A-unit.


Model         Year   Wheel        Horse  Notes
              Built  Arrangement  Power

Box Cab       1935     B-B        1800
EA/EB         1937-38  A1A-A1A    1800   Baltimore & Ohio
E1A/E1B       1937-38  A1A-A1A    1800   Santa Fe
E2A/E2B       1937     A1A-A1A    1800   Union Pacific
E3A/E3B       1938-40  A1A-A1A    2000
E4A/E4B       1938-39  A1A-A1A    2000   Seaboard
E5A/E5B       1940-41  A1A-A1A    2000   Burlington
E6A/E6B       1940-42  A1A-A1A    2000
E7A/E7B       1945-49  A1A-A1A    2000
E8A/E8B       1949-54  A1A-A1A    2250
E9A/E9B       1954-64  A1A-A1A    2400
TA            1937     B-B        1200   Rock Island/for Rocket trains
F3A/F3B       1946-49  B-B        1500
F7A/F7B       1949-53  B-B        1500
FP7           1949-53  B-B        1500   slightly longer than F7A/no B-units
F9A/F9B       1953-60  B-B        1750
FL9           1957-60  B-A1A      1750   New Haven/dual power
BL2           1948-49  B-B        1500   "Branch Line" predecessor to GP7 model
GP7           1950-54  B-B        1500
GP9           1954-59  B-B        1750
GP18          1959-63  B-B        1800
SD7           1952-53  C-C        1500
SD9           1954-59  C-C        1750
SDP35         1964-65  C-C        2500
SDP40         1966     C-C        3000
SDP45         1967     C-C        3600
FP45          1967-68  C-C        3600
GP40P         1968     B-B        3000


Model         Year   Wheel        Horse  Notes
              Built  Arrangement  Power

DL-103        1939     A1A-A1A    2000   Rock Island
DL-105        1940     A1A-A1A    2000
DL-107        1939-42  A1A-A1A    2000
DL-108        1939-42  A1A-A1A    2000   B-unit
DL-109        1941-45  A1A-A1A    2000
DL-110        1941     A1A-A1A    2000   B-unit
PA-1/PB-1     1946-50  A1A-A1A    2000
PA-2/PB-2     1950-53  A1A-A1A    2250
RS-1          1941-60  B-B        1000
RS-2          1946-50  B-B        1500
RS-3          1950-56  B-B        1600
RSC-2         1946-50  A1A-A1A    1500
RSC-3         1950-55  A1A-A1A    1600
RSD-4         1951-52  C-C        1600
RSD-7         1954-56  C-C        2400
RS-11         1956-61  B-B        1800
RS-36         1962-63  B-B        1800
C-420         1963-68  B-B        2000


Model         Year   Wheel        Horse  Notes
              Built  Arrangement  Power

DR-6-4-2000   1946-48  A1A-A1A    2000   B-unit also available
DRX-6-4-2000  1946-48  A1A-A1A    2000   Central of New Jersey/double cab
DR-12-8-3000  1947-48  2-D-D-2    3000
DRS-4-4-1500  1947-50  B-B        1500
DRS-6-4-1500  1946-48  A1A-A1A    1500
RS-12         1951-56  B-B        1200
AS-616        1950-54  C-C        1600


Model         Year   Wheel        Horse  Notes
              Built  Arrangement  Power

Erie Built    1945-49  A1A-A1A    2000   A-units and B-units available
CFA-16-4      1950-53  B-B        1600   B-unit model CFB-16-4
CPA-20-5      1950     B-A1A      2000   only A-units built
CPA-24-5      1951-52  B-A1A      2400   only A-units built
H-15-44       1947-50  B-B        1500
H-16-44       1950-63  B-B        1600
H-16-66       1951-58  C-C        1600
H-24-66       1953-57  C-C        2400


Model         Year   Wheel        Horse  Notes
              Built  Arrangement  Power

U28CG         1966     C-C        2800   Santa Fe
U30CG         1967     C-C        3000   Santa Fe


Model         Year   Wheel        Horse  Notes
              Built  Arrangement  Power

LRS 1200      1950-51  B-B        1200

Diesel locomotives would often run in multiple. And many railroads with their E-units and F-units, assigned a single number to a set of locomotive units, semi permanently coupled together. And each unit would have a letter following the overall number. Usually with an "A" for the lead unit, a "B" for the following unit, and a "C" or a "D" for any following units. A locomotive set might have a leading A-unit and only B-units behind, to give a passenger train a sleek streamlined look. Or often a locomotive set would be bidirectional, with an A-unit at each end and the cab at each end of the set.

But over the years, many railroads ceased to keep their locomotive sets together. Including railroads operating commuter trains in Chicago, which rarely had more than one locomotive. Some E-units might have been numbered with "A" or "B", but never actually operated coupled together for any significant amount of time, if at all. Computerization eventually led to railroads eliminating number schemes which used letters.

With the passenger locomotive roster pages at this section, usually the original numbers are used. Although for some railroads, a later numbering scheme is used if it simplifies how information is presented. Semi permanently coupled sets are presented as such. With the different letters running together for the locomotive number, and a sequence of A's and B's with the model designation reflecting the A-units and B-units.

Roster pages are complete for the E-units and other locomotives originally built specifically for passenger service. Also included are other known locomotives, equipped with steam generators for passenger service. Information is mostly complete for F-units. But information may be less accurate for road switchers (GP and RS type locomotives). With road switchers, with a locomotive order, not all locomotives in a consecutively numbered series were equipped for passenger service. Although every effort was made to verify accuracy and research where gaps existed. Many of those locomotives later had their steam generators removed and were reassigned to freight service.

Some locomotives were built using trade in components, often resulting in a horsepower reduced from the standard model at the time. Mostly E-units. Those locomotives have the model designation followed with the letter "M", for modified. For example, E8AM.

Additional web sites with further information on diesel locomotives, including additional technical details and serial numbers.