I've always wondered this. When I'm on a train, I can barely get a mobile signal most of the time, and obviously not at all in a tunnels.

How does wifi manage to work?

It will still mostly be over 3G / 4G networks (although I think some uses satellite aswell, I may be wrong on that though).

However there are a couple of differences compared to your mobile:
1 - There isn't the restriction on size / other features that exists when it comes to mobile phones. So the hardware that contains the antenna etc can be much larger and better designed to pick up signal where your mobile probably wouldn't
2 - Mainly newer trains (especially the Voyager family) seem to act like mini Faraday cages, blocking a lot of the signal from even entering the train. As the hardware on the train can be outside on the roof etc, it isn't affected by this.

Yeah i believe it is something like the media use (like when they were sending live feeds from the moving election campaign busses).
They have a system that can switch between or merge the various 3G/4G networks on the fly.
Also, as was said, the antenna will be outside the train and as big as it needs to be for very good reception. Bit like how my Huawei router gets a much better signal than my phone.

What about tunnels? Do they have repeaters in there?

It doesn't. Or, it didn't when I tried it the other week anyway!
Furthermore EE's signal couldn't seem to keep up with the speed of the train despite it apparently being "mobile enhanced" (not sure what that is) - 5 bars of actual signal but no throughput (on either phone or osprey hotspot) unless the train was stationary. I spent a disappointingly boring 3.5 hours!

The Channel Tunnel has repeaters IIRC, at least for the French networks.

If I recall correctly one bore of the Channel Tunnel carries the (some?) English mobile signals while the other carries French!

Yep, that's correct. Vodafone and EE southbound and the three biggest french Northbound

You should get signal from one of the networks bouncing in through the tunnel opening surely? most tunnels aren't that long.

The BBC used the same technology when they did the Olympics torch coverage online, they broadcast video of the torch from a vehicle as it travelled all over the country.

EE even sell a service specifically for broadcasters with 4G that is prioritised traffic I think.

Trains like the Pendolino in operation on the West Coast Mainline are truly shocking for signal. However for the internal Wifi they use big antennas, still shocking, I can't remember who they use now but Virgin used to use T-Mobile/EE and it would barely give any speed for the vast majority of the journey, they used to have maps showing on the line map where they expected good service and slow service and no service.

You'll lose signal quickly if it isn't just a small tunnel under a road.



Virgin used to have on board amplifiers for certain networks. Orange may have been one of them?

I'd guess it depends on the generation of equipment. I've used FGW Wifi and it's been okay - and as it is brand new it likely has LTE and even satellite capability. Don't expect to stream video though, as they use traffic management to stop it

I was on a Virgin Train last week. WiFi was useless for much of the journey, handset signal was patchy at best, even when still in London. They still have stickers everywhere saying "WiFi from T-Mobile". Has no one told them that brand is dead and buried?

I have a feeling they did, but they were probably 2g only and I don't think all the networks. I don't have much luck on either Vodafone or o2 for work, even phone calls drop out. I used to have a work issued MBB stick on EE but that went for some reason.


It's been like that for years, despite MBNL having the best 3g coverage it simply doesn't work well travelling at 125mph, I think 4G is meant to be slightly more resilient at high speeds so I'd hope that before long with higher 4g power levels there'll be some improvement. Whenever I'm down in London I effectively lose 4 hours of working that could be put to much better use if there were the proper infrastructure.

You're right, of course. I used to live in Stoke and travel a bit more regularly on the West Coast, it didn't work then either! Must have been.... 2009?

Before the dissolution of the networks Orange developed an arrangement so onboard amplifiers could be installed in the train carriages. The only stipulation was that it had to be cross network, so Three, Vodafone et al obstensibly appeared to increase coverage cost free. Turned out it never worked like that and Orange & T-Mobile were generally the only ones to see an improvement. There was a claim when Orange launched the service that a mobile phone only lost signal and dropped a call twice between Euston and Glasgow.......what they didn't say is how shit the service quality was....better off saving battery by putting phone in flight mode. I am lead to believe it has improved since 2009.


Its interesting you should mention this, back in early March me and the hubby headed to London for a few days. I still had one of the first EE 100GB Dan & Phil sims knocking around. On the journey there and back I didn't lose signal once, even better I would say I was only on 3G 1/5 of the time, it was 4G all the way through. Admittedly I was using a Lumia 1020 and tethered to it. I really was surprised at the service level and quality, admiring how much ground EE has made. Never in a million years did I expect to get a strong signal on a train outside London. It might have been the equipment on the Pendolino trains has been upgraded. If it wasn't for the fact I am with Vodafone due to a discount I would have no problems moving to them, even if the pay monthly allowances a shite.

I don't generally take my personal phone with me when travelling around, it's just another thing to keep track of when trying to rush around Central London avoiding tourists. My old MBB thingy was Orange and later MBNL 3G only and worked when visiting sites and touring around but I never got to try on 4G and I am with Three still on my lovely One Plan so I won't be switching. It is interesting though because they've presumably prioritised it for it to be that well done and I can imagine a lot of businesses taking them up on that, "We can give you a rock solid internet connection whilst travelling the country, turning your employees' dead time into productive time".

I find books still work very well on trains

The reason there is often no connection at speed is to do with a combination of doppler effects, and rapid signal fade, this thread gives some background, and a link to a report from Korea

http://forums.whirlpool.net.au/archive/1837375

4G can work quite well at very high speeds, it all depends on how close the mast is to the track.

I wonder how 800MHz 3 4G works on trains.

Or how far ? Having the mast right next to the track isn't going to be very helpful, particularly if the track is straight ?

Because the ones which are designed to cover the railway have 2 sectors pointing in the two directions. It is also a bit easier to get masts near railways as the landowners are a bit more accommodating and I wouldn't have thought the planning system was too much of a problem either.

No, but if you're sat on a train, on a straight track, there's an awful lot of 'train' the signal has to pass through to get to you. If the mast is a mile or so away from the track, you are going to be line of sight for much longer periods.

Having a mast next to the track, and firing down it, is only really going to benefit the driver (until the front of the train has passed !)

Makes perfect sence for the train company UHF comms systems to use that method of course, and you often see a mast with two yagis firing up and down the track

We're talking about the WIFI services which these operators run, the mobile antennas are not inside the carriages. A lot of train site masts do only have 2 sectors pointing in the direction of the track, take a look next time you're around a railway.

Well, I was responding to direct reception of the networks on a train, which is what some in this thread are talking about. Yes, I've seen the two sector masts, as I say, I don't think they can be that effective (except for serving the roof mounted antennas used for the on board WifI networks).

The majority of lineside lattice masts with two sector panels pointing up and down the track are upgraded GSM-R sites:

https://upload.wikimedia.org/wikiped...bergavenny.jpg

The old GSM-R sites used to use two yagi antennas, but these are slowly being dismantled.