List of ALCO diesel locomotive classes explained

The American Locomotive Company (ALCO), based in Schenectady, New York, United States produced a wide range of diesel-electric locomotives from its opening in 1901 until it ceased manufacture in 1969. This is a list of ALCO locomotive classes.

For individually notable locomotives, please see List of locomotives. There are numerous individual ALCO locomotives that are preserved in museums or heritage railways. In particular please see sublists List of preserved locomotives in the United States and List of preserved locomotives in Canada.

Boxcab locomotives

Model	Build date	Total produced	Wheel arrangement	Prime mover	Power output	Image
	1924–1928	26		Ingersoll-Rand 10x	300-1NaN-1
	1925–1928	7		Ingersoll-Rand 10 × 12 (×2)	300-1NaN-1 × 2
	1928	1			300-1NaN-1
	1931	6		McIntosh & Seymour 9½ x 10½	300-1NaN-1

Switchers

Model	Specification	Build date	Total produced	Wheel arrangement	Prime mover	Power output	Image
	—	1931–1938	11		M&S 6-330	300-1NaN-1
	—	1931	1		6-531	600-1NaN-1
	—	1931–1939	78		6-531	600-1NaN-1
	—	1937–1939	21		6-531T	900-1NaN-1
	—	1939–40	43		6-538	660-1NaN-1
	—	1939–1940	34		6-538T	1000-1NaN-1
	E-1530	1940–1950	543		6-539	660-1NaN-1
	E-1540	1940–1950	1462		6-539T	1000-1NaN-1
	E-1530A	1950–1953	137		6-539	660-1NaN-1
	E-1540A	1949–1957	651		6-539T	1000-1NaN-1
S-5		1951	1		6-251	800-1NaN-1
	DL-421	1954	7		6-251A	800-1NaN-1
	DL-430 (1st)	1955–1960	126		6-251B	900-1NaN-1
	DL-431/DL-461	1956	2 sets		6-251B × 2	900-1NaN-1 × 2
	DL-440	1958–1969	57		6-251B	1000-1NaN-1

Cab units

Model	Specification	Build date	Total produced	Wheel arrangement	Prime mover	Power output	Image
	—	1935, 1937	3		6-531	600hp
—		1939	1		6-538T × 2	10002NaN2 × 2
—		1940	3		6-539T × 2	10002NaN2 × 2
—		1940–1941	8		6-539T × 2	10002NaN2 × 2
—		1941	3		6-539T × 2	10002NaN2 × 2
—		1941–1945	62		6-539T × 2	10002NaN2 × 2
—		1942	1		6-539T × 2	10002NaN2 × 2
—		1945	2		12-241	15002NaN2
—		1945	1		12-241	15002NaN2
	DL-204, DL206, DL-208, DL-208A, DL-208B	1946–1950	396		12-244A, B	15002NaN2
	DL-208C	1950	21		12-244C	16002NaN2
	DL205, DL-209, DL-209A, DL-209B	1946–1950	213		12-244A, B	15002NaN2
	DL-209C	1950	16		12-244C	16002NaN2
	DL-212, DL-212A	1950–1956	308		12-244D, G	16002NaN2
	DL-212, DL-212A	1950–1951	54		12-244D	16002NaN2
	DL-213, DL-213A	1950–1956	181		12-244D, G	16002NaN2
	DL-213, DL-213A	1950–1956	25		12-244D	16002NaN2
	DL-304, DL-304A, DL-304B	1946–1949	169		16-244	20002NaN2
	DL-305, DL-305A, DL-305B	1946–1949	39		16-244	20002NaN2
	DL-304C, DL-304D	1950–1953	81		16-244	22502NaN2
	DL-305, DL-305D	1950–1953	8		16-244	22502NaN2

Four-axle road switchers

Model	Specification	Build date	Total produced	Wheel arrangement	Prime mover	Power output	Image
	E-1641A	1941–1960	469		6-244T, 6-539T	10002NaN2
	E-1661, E-1661A, E-1661B	1946–1950	338		12-244	15002NaN2
	E-1661C	1950	30		12-244	16002NaN2
	E-1662, E-1662A, E-1662B	1950–1956	1272		12-244	16002NaN2
	DL-701	1956–1961	355		12-251	18002NaN2
	DL-640	1959–1962	27		16-251	24002NaN2
	DL-721	1961–1962	35		12-251	20002NaN2
	DL-701XAP	1962–1963	40		12-251	18002NaN2

Six-axle road switchers

Model	Specification	Build date	Total produced	Wheel arrangement	Prime mover	Power output	Image
		1946	4		6-539T	10002NaN2
	E-1641	1946	6		6-244T, 6-539T	10002NaN2
	E-1645	1942-1943	44		6-244T, 6-539T	10002NaN2
	E-1646	1944–1945	100		6-244T, 6-539T	10002NaN2
	E-1661, E-1661A, E-1661B	1946–1950	86		12-244	15002NaN2
	E-1661C	1950	5		12-244	16002NaN2
	E-1662, E-1662A, E-1662B	1950–1955	99		12-244	16002NaN2
	E-1663, E-1663A, E-1663B	1951–1952	36		12-244	16002NaN2
	E-1664, E-1664A, E-1664B	1952–1955	204		12-244	16002NaN2
	DL-600	1954	2		16-244	22502NaN2
	DL-600A	1955–1956	27		16-244	24002NaN2
	DL-702	1956–1963	171		12-251B	18002NaN2
	DL-600B	1956–1960	75		16-251B	24002NaN2

Century series

ALCO announced its "Century Series" of diesel locomotives in 1963 as a leap forward in power and reliability, an attempt to compete more aggressively with GM-EMD and GE in the marketplace.

Model	Specification	Build date	Total produced	Wheel arrangement	Prime mover	Power output	Image
	DL-415	1966–1968	26		8-251F	15002NaN2
	DL-721A	1963–1968	131		12-251C	20002NaN2
	DL-640A	1963–1967	98		16-251B	24002NaN2
	DL-640B	1964–1966	91		16-251C	25002NaN2
	DL-430 (2nd)	1967–1968	16		16-251E	30002NaN2
	DL-628	1963–1968	186		16-251C	27502NaN2
	DL-630	1965–1968	133		16-251E	30002NaN2
	DL-636	1967–1968	63		16-251E	36002NaN2
	DL-855	1964	2		Dual 16-251	55002NaN2
	DL-856	1964	1		Dual 16-251	55002NaN2

Diesel-hydraulic locomotives

Military locomotives

Locomotives export and not exported

Model	Specification	Build date	Total produced	Wheel arrangement	Main engine	Power output	Image
FCA-3	DL212	1951-1953	23		12-244D	16002NaN2
FD-3	DL500	1953	3		12-244D	16002NaN2
FD-3	DL500A	1955	16		12-244D	16002NaN2
FPD-5	DL500A	1955–1956	12		12-244	16002NaN2
		1957	25
FD-6	DL500B	1958–1968	141		12-251 12-251B	16002NaN2 18002NaN2
SEK class A-301					12-251B	18002NaN2
FD-7	DL500CI	1957-1958	99		12-251B	18002NaN2
		1957-1959	59
FD-9	DL500D				12-251b	18002NaN2
FP-9	DL500G	1965–1973	131		12-251B	18002NaN2
FPD 9		1964-1966	23			21802NaN2
RSD-8 (NSW 48)		1959–1970	212		6-251D	1060-1NaN-1
RSD-8		1958–1959	103		6-251D	1060-1NaN-1
RS-8		1966–1974	74		6-251D	1035-1NaN-1
SEK class A-201		1961–1962	10	B-B	6-251D	1035-1NaN-1
		1963	40		6-251D	1350-1NaN-1
		1963	70(MLW)		6-251D	1350-1NaN-1
		1965–1967	76		ALCO 251-D	1200-1NaN-1
		1961–1969	100 (#6020-#6049 and #6105-#6129)		6-251D	1300-1NaN-1
ENAFER RSD-35		1963, 1969, 1974	26			1200-1NaN-1
DL535E		1969 completed by MLW	10		6-251D	1200-1NaN-1
		1963	115
RSD-36		1978	20		6-251D	1200-1NaN-1
Tunisian Railways 040-DK
RSD-37		1965	12		6-251D	1200-1NaN-1
SEK class A-9101		1965		C-C	6-251D	993kW
		1957–1959	130		ALCO 12-251B	1950-1NaN-1
RSD-16		1960–1968	77		12-251B	1830-1NaN-1
SEK class A-321		1961–1970	117	C-C	12-251C	1470kW
	DL550 DL550K	1964	1
DL-560		1963–1964	12		12-251B	2600-1NaN-1
		1966	3
WDM-2/ALCO RSD-29		1962-1997	2962, 18040 – 18079 (1962), 18112 – 18232 (1962 – 1963), 18245 – 18298 (1964 – 1965), 18337 – 18361 (1965)		16-251B	2600-1NaN-1
		1974	15

Montreal Locomotive Works Export locomotives

Model	Specification	Build date	Total produced	Wheel arrangement	Prime mover	Power output	Image
		1972–1979	74		MLW 8-251A	1200-1NaN-1
		1973–1980	145		MLW 12-251C	2000-1NaN-1
		1975–1983	69		MLW 12-251E	2400-1NaN-1
		1972–1982	32		MLW 12-251E	2400-1NaN-1
OSE class A-451		1972–1978	33		MLW 12-251C	2750-1NaN-1
OSE class A-501		1974–1980	10		MLW 16-251E	3600-1NaN-1
		1973–1982	100		MLW 12-251E	2000-1NaN-1	Double End Cab Units
		1973–1983	33		MLW 16-251E	2400-1NaN-1	Double End Cab Units
		1978–1980	10		MLW 16-251C	2750-1NaN-1	Double End Cab Units
		1978–1982	33		MLW 16-251E	3000-1NaN-1	Double End Cab Units

External links

• ALCOWorld