Pointy thing on trains?

[willas00]

I was sat at Cheltenham Spa the other day and an XC Class 220/221 pulled into the station. I noticed this pointy thing on top of the train which I've noticed before and always wondered what it was.

A GWR Class 158 then pulled in and I noticed it had the same pointy thing on top.

I originally thought it was to do with on board WiFi but the GWR Class 158's don't have WiFi.

I've attached a picture of the so called pointy thing.

Does anyone actually know what it is? I gather is must do something.

Cheers

 

[61653 HTAFC]

I think it's a GSM-R receiver for the cab radio. No doubt someone will confirm this or put me right.

 

[MrPIC]

correct

 

[WarrenTManager]

Bang on. The standard fitment is Kathrein 741009