Radio interference around Stratford being one issue it seems.
Although it’ll be several months I thought before trains from Stratford will delve into the tunnels.
Although it’ll be several months I thought before trains from Stratford will delve into the tunnels.
What's a bit strange is that they've been running the same trains with passengers on from Liverpool Street through Stratford for more than 2 years, with passengers, as TFL rail. But I guess they had to upgrade the signalling around Stratford to work with the trains coming through the core, and that is still buggy
https://anonw.com/2021/08/12/the-crossrail-tunnel-portal-at-...
From there the train will travel underground to the Liverpool St - Moorgate station.
There’ll still be Elizabeth line trains travelling into Liverpool St station but there’ll be terminating.
Fun fact there’s the large ABBA venue going up at Pudding Mill Lane.
https://www.ourbow.com/abbas-virtual-comeback-show/
The things one misses when not commuting.
No one has called it the ABBAtoir yet, but I’m waiting to see who’ll be the first to come up with that name.
I think you mean Pudding Mill Lane?
Pudding Lane was where the Great Fire of London started.
it was originally buried so that it could connect up with the Metropolitan Railway (today's metropolitian line on the London Underground)
this was so that in 1875 the Met could use the mainline railway station as terminus (whilst their own was under construction)
Trains from Stratford will still be terminating at the same high-level platforms at Liverpool Street. Through running into the core tunnels (and thus a signalling system change) will come later.
This means that the boundary between the mainline signalling and the new CBTC signalling in the core is at Stratford. But this only applies to trains taking the new route; services on the existing GEML/Shenfield Electric lines continue to use mainline AWS/TPWS signalling, which is why there hasn’t been any impact on services to date.
I’m sure you can appreciate the impracticality of building a train to signalling system interface that uses cables!
ETCS can use cable loops, but for full functionality a radio data connection is required.
In the case of Crossrail the core (new tunnels) use CBTC signalling, I think based on Siemens TrainGuard - I think the specification of the project predates ETCS being proven as a viable solution for this particular kind of service. The services leaving Stratford to the East use TPWS/AWS in common with most services on the UK mainline network.
The challenge is in the transition between the two systems, as I understand it - anything out of the ordinary and the train will of course come to an immediate halt.
So can't they use the power cables for comms?
I’m getting out of my depth, but I’m sure I’ve seen at least one signalling system that uses the track circuit as a data signalling channel to the train to provide in-cab signalling, so I’d guess it’s at least theoretically possible.
I’d imagine it would have much the same challenges as radio in practice though - interference from poor connections and ambient noise, not to mention your channel is basically a massive antenna.
Reminds me of Feyerabend's "Against Method".