Highly Dangerous (1950): Film Review | Lost Eras

1hr 30mins
Dir: Roy Baker
Starring: Margaret Lockwood and Dane Clark

A British lady entomologist tries to stop a biological attack with the help of a US journalist

This spy thriller features an early scene that is filmed outside Taplow station and just visible passing through in one shot is an express hauled by a GWR 4-6-0, though it is partly obscured.

This is Taplow station on the GW main line in Buckinghamshire. This building on the up side along with the footbridge have all now been swept away.
As Margaret Lockwood and Naunton Wayne discuss proceedings a GWR express passes through on the up main. The locomotive smokebox is just visible to the left of the steering wheel and the roof of the signal box.
This cropped image shows the locomotive somewhat more clearly