159s used to be a separate entry on the traction card, and are on mine although now you can drive them with just 158s on there. There used to be some differences such as the 159s didn't have remote supply installed until later on and some minor things such as the location of switches (eg the remote supply on a GWR 158 unit is inside the cab, on a SWR unit it is in the cupboard in the vestibule behind the cab, and the doors behind the lead cab are unavailable to passengers when the driving desk is keyed in as well as the cabless middle vehicles, 158798 excepted later on.) There are no significant differences between them so GWR staff who signed 158s were given a paper brief detailing the slight differences. On reading this you were deemed competent to work 159s as well as 158s.
I like driving the hired in 159/0s with the 400hp engines. You have to shut off power at places that you wouldn't have to with the usual GWR 350hp 158s to prevent speeding.
