SP 6008B-6010B
These cabless booster units were built with alpha suffixes with associated A-units with corresponding A & C alpha suffixes. They were initially operated in ABC sets, but were never drawbar-coupled. They were renumbered to SP 5913-5915 in 1949.
SP PB-1's - class DP-6 - ALCO-GE const. numbers 75786-75788:
| Original number | 1949 number | notes |
| SP 6008B | SP 5913 | |
| SP 6009B | SP 5914 | |
| SP 6010B | SP 5915 |