The Alaska Railroad's first diesel locomotives were #1000 and 1001. These were new Alco RS-1 units rated at 1000 hp dedicated for the regular Whittier run through the long tunnels.
These were the only RS-1 units among a roster of many Alco road switchers which were military surplus RSD-1 units obtained with six wheel trucks and squashed cab for close clearance.      1000 and 1001 both went through a series of modifications and four paint jobs ending with the short nose being chopped when they were assigned as yard switchers in 1967.

Here is a series of models representing the four paint schemes and modifications.

No. 1000 in 1944	No. 1001 in 1950	No. 1000 in 1962
No. 1000 at retirement	RS-1 long hoods	RS-1 short hoods