[quote="thesweetcheat"

The horse does absolutely appear to be galloping in the same direction as the train.[/quote]

But you know that is just an impression and not the basis for a theory about the horse and any change in it's direction that might be assumed from your observation .

Although I was a regular commuter between Bath and London for some time , I have no doubt that you have travelled that route far more often than I.
But I wouldn't suggest that gave me any better understanding of the problems discussed than someone who had never set foot or sat arse in a train in the area .