What are these boxes on the roof of some class 159s?

[Breadface]

Something I've noticed while looking at the 159 units is that some seem to have these boxes on the roof at the inner end on 1 driving coach per unit, It appears to be 3 Boxes with a cable or pipe running in-between them

It would be great if someone could explain what these are and which units have them because as far as I'm aware it seems to be a handful of /0s and /1s that have them

Images below to see them, and yes I've ripped them straight from google images

 

[westcoaster]

Wifi receivers

 

[DarloRich]

snorkel fitting for Dawlish services?

 

[158747]

GWR 158s have them also.

 

[PHILIPE]

GWR 158s have them also.

And TFWs, EMRs and Northern 158s

 

[Breadface]

Thanks for the info

I haven't seen any of them on EMRs, TFWs or Northern's but watching some videos I can see GWR had them and even in FGW livery they had them

 

[100andthirty]

Wifi receivers

Pedantically, they are likely to be 4G antennae, possibly co-housed with wifi antennae. The latter's use is to transmit train or CCTV data in the depot with a bigger bandwidth than is normally available though 4G.

 

[TRAX]

Isn’t onboard wifi converted from 4G received by the train anyway ? Wifi isn’t emitted in the middle of nowhere, so are they really receivers per se ?

 

[100andthirty]

Isn’t onboard wifi converted from 4G received by the train anyway ? Wifi isn’t emitted in the middle of nowhere, so are they really receivers per se ?

All the comms systems are two-way, but basically the answer to the question is yes. The on board telecoms system communicates with customer's devices via wifi; there will be some sort of ethernet to distribute signals from a central hub to wifi antennae spread down the train interiors and to communicate with train equipment that collects data. he onboard telecoms system communicates with the outside world via 4G - sometimes multiple mobile modules to get the best possible signals from the various 4G providers.