Gas cylinders near railway line

[rockford]

I've just passed through Great Chesterford station towards Bishop's Stortford and at the side of the track, shortly after the platform, there were four banks of four propane gas cylinders spaced about 100m apart.
What would these be for? I couldn't see what they were connected to - it certainly wasn't the station building itself - they were on the other side.
No real reason for asking - just curious.
Thanks
Andy

 

[Old Timer]

Possibly for points heating.

Are you certain they were not compressed air cylinders supplying air for electro-pneumatic points.

 

[swt_passenger]

If permanent looking, and roughly where the crossovers are, it's likely they are for point heaters.

 

[rockford]

They were definitely Calor propane cylinders, and they were in permanent-looking breeze block enclosures.
Thinking about it, the four locations would tie in with the points, so it's likely that's what they were for.
Thank you!