The class O locomotives were originally designed in the early 1980s when it looked like the now-ancient classes 240 & 280 might be reaching the end of their careers. Alas, this was not to be the case, and then the PV&T started to expand like crazy, so the design was filed away for later.

In 2001, this design was updated to include 1066mm (42 inches)-wheeled variants of the Portland A4R truck and a multi-system drivetrain so the units can run under all of the tensions across the Parsons Vale system.

They’re lightweight little things; maybe 90 tons at most, and only putting out 1400 HP, but ideal for carload customers on the TdM & D&H South.

Five were built in 2005 (2 for the TdM, 1 for the LW&C, and 2 for the D&H), three were built in 2007 (two for the ORRC, 1 for the SVT), and two more were built for the ORRC in 2023

All are in service.