I know one case with an electric locomotive:

NSB (Norwegian State Railway) bought a number of Re 460 from Switzerland some years ago.

The Swiss one has the driver's seat on the right hand side.


The Norwegian one on the left hand side.


It can be noticed in the photos, if you look very carefully.

On Dutch and german steam locos, the drivers position is on the right hand side. You can easily tell, because on the driver's side is a long rod that goes from about 1/3 of the cab height from the bottom, to a place just behind the expansion link(the curved, nearly vertical bit that rotates around a central privot). This rod is the reverser, and is always on the driver's side.
However, in New Zealand, trains drive on the left hand side of the track. But, the driver's side is also on the right hand side
Of course, in steam days, the fireman was not only minding the fire, he was also required to keep an eye out on the track ahead. I have been in a few cabs on the local vintage railway, at every crossing the driver shouts at the fireman: "Your side clear?" to which the fireman replies "All clear"! before the driver opens the throttle.

I cannot say for sure, but with a cab that is at the front of the loco, like the Re 460, it doesn't matter on which side the driver sits, because either side affords (almost) the same visibility.

Of course I meant the other way around



This is a photo made by me on August 7th 2010 at 3PM in Kristiansand, the train from Oslo to Stavanger.
At Kristiansand station the trian direction is reversed, so the locomotive is disconnected from one end of the train, to be connected to the other end.