What was that movie? (Creepy children edition)

Question

I saw a movie on television as a kid and have wondered for years what it was. I haven't been able to find any clues online. What I remember about the plot is that it begins with two men in the last railcar of a train that becomes separated from the rest of the train and rolls away down the tracks out of control until it comes to rest in a small town. They discover all the children have some odd mutation(?) so that they have (from what I remember) dark rings under their eyes and elongated heads. They somewhat remind me of the children in Village of the Damned -- but it definitely was not that movie. The children are also very intelligent and mature -- adult-like -- and may possess some sinister supernatural powers (again, like in Village of the Damned), but I can't remember the specifics. There's also woman in this town that the men meet who's trying to help these children, to liberate them from whatever this condition is that's possessing them. In the end, I remember there's something of a celebration when the children do become liberated. I remember only a few other scenes, like where one of the mutant boys becomes threatening toward one of the men when he realized that the man has taken photographs of... whatever is going on in this town with the children. If I had to guess, I think the movie was from the 60's (possibly late 50's or early 70's). Also, I've wondered if it could have been an episode of a TV series, but I really think it was a movie. Can anyone help?

Answer 1

It sounds like The Gamma People (1955) British-American production.

A train passenger car carrying a reporter and his photographer mysteriously breaks away from its locomotive, accidentally ending up on a remote sidetrack in Gudavia, an isolated Ruritanian-style, one-village Eastern Bloc dictatorship. The newsmen discover a mad scientist using gamma rays to turn the country's youth into either geniuses or subhumans, all at the bidding of an equally mad dictator.

https://en.wikipedia.org/wiki/The_Gamma_People1

The film starts with two journalists, burly American Mike Wilson (Paul Douglas) and effeminate British Howard Meade (Leslie Phillips), sitting at a game of chess in their train compartment on their way to cover an event in Salzburg. However, their train car mysteriously gets detached from the rest of the train, and when a group of boys pull the … what’s the thing … that lever that switches between different tracks at junctions – their car rolls into the territory of Gudavia.

https://scifist.wordpress.com/2017/03/08/the-gamma-people/2

If the movie you remember is The Gamma People (1955), then it is certainly an unusual and almost unique movie if my memory of it is accurate.