Sevenoaks Tunnel Mobile Phone Reception

[Terry Tait]

I went through Sevenoaks Tunnel earlier and the lady across from me was talking on her phone all the way through it, I checked both of my phones and neither had any service, is there something I don't know or is she one of life's eccentricities?
The tunnel is quite deep and very long and we were on a 465.

 

[bramling]

I went through Sevenoaks Tunnel earlier and the lady across from me was talking on her phone all the way through it, I checked both of my phones and neither had any service, is there something I don't know or is she one of life's eccentricities?
The tunnel is quite deep and very long and we were on a 465.

On a train fitted with wi-fi, and using a phone network which offers wi-fi calling?

Still something whose reliability IME is rather patchy, so if so she’s done well to manage a call right the way through a tunnel!

 

[Aictos]

On a train fitted with wi-fi, and using a phone network which offers wi-fi calling?

Still something whose reliability IME is rather patchy, so if so she’s done well to manage a call right the way through a tunnel!

I’m not in that location at the moment but as I can barely get a signal atm with my operator my phone uses WiFi calling instead so it’s very likely that’s what this passenger was doing.

As to saying it’s unreliable? Maybe that’s operator dependent as I use Three and it works fine even if I use the WiFi on the Underground I get a constant connection between 4G and WiFi Calling.

The other thing as well is maybe Network Rail put extra infrastructure in that tunnel to improve mobile coverage?

 

[Mordac]

Maybe she was talking to herself while pretending to be on the phone.

 

[KingJ]

Although using the WiFi can help to maintain calls on trains due to the mobile antennas for it being high up on the roof and outside the train body itself, even they would not maintain connectivity through the Sevenoaks Tunnel currently. There is no in-tunnel solution, nor are the masts for any network at either end positioned to give coverage directed into the tunnels.

I suspect they were either recording a message to send via a messaging app, or not aware that the call had dropped.

There was an upgrade to the EE/Three mast near the entrance to the Polhill Tunnel a while back, which significantly improves coverage in the cutting to the North of the Polhill Tunnel, and indeed reaches in to the Chelsfield Tunnel - i've been able to maintain calls going through the Chelsfield Tunnel since the upgrade.

 

[Wagonshop]

Going back about 25 years I had small BR phone which worked in some tunnels used the BR network the same system that was fitted to loco's EMU's. I could call all over BR and get a BT line
Could it be rail staff .

 

[Trackman]

The signal could be bouncing, but that tunnel is about 2 miles long.

Years ago I was walking down the steps to the Charing Cross branch southbound platform at Euston and my phone rung!
1 bar and no wifi I may add, but when you turn left and on the way down the signal stops.

 

[ess]

Back in the 90s there were BT Phonecard phones on TransPennine 158s. Did they work in the tunnels?

 

[Tio Terry]

Going back about 25 years I had small BR phone which worked in some tunnels used the BR network the same system that was fitted to loco's EMU's. I could call all over BR and get a BT line
Could it be rail staff .

NRN? Not the best system in the world but good for BR.