ETCS uses wired connections through the train, it's only the connection between the train and the control centre that's radio.
I believe that for the ETCS signalling, connections between the signalling centre and the track are wired; and then wireless connections are made between the track and the underside of the train, and even then, the [radio signals] are very strong (in the National Railway Museum's video of a 700 at its depot, the presenter pointed out that he could only go under the unit because the ETCS [radio signals] were not in use, so it was safe to do so.)
I'll just point out that in the USA the AAR multiple unit interface is quite capable of connecting a brand new all-computerised loco to a 1950s all old relays one from a different manufacturer long out of business, and they will all work together from either cab. AAR is American Association of Railroads, a trade association of operators and builders, and they just determine each generation of control compatibility, something one wishes bodies like the RSSB would have done (otherwise why have 'Standards' in their name?). Not only USA manufacturers, but those from Asia (where nowadays much USA equipment seems to come from), and from Europe, the likes of Siemens etc, have to comply with AAR standards, otherwise nobody in the USA will buy them, and it extends to Australia etc. They can put their own software internally, but for MU connections it's all AAR. It's all completely up to date for modern stock. I understand it's a considerable task for AAR's own engineers, but they manage it. I believe Class 66 were certainly originally delivered with AAR MU, but some operators have modified it, for whatever reason.
Don't 68s and 88s use AAR MU standards?
Realistically, I doubt it is.
That article is talking about radio-linked 'End-of-train' devices (EOT/EOTD, also known as FREDs), which replaced cabooses decades ago, and are completely separate from the remote control system for 'distributed power' locomotives.
There are colour schemes that go well together - and then...
ETCS level 2 (as fitted on the Cambrian and Thameslink and being fitted on the southern ECML) uses vital radio links to convey movement authorities to replace trackside signals. These go over GSM-R currently and will transition to whatever replaces it.
But does AAR cover passenger functions like information displays and alarms, or train management systems monitoring and controlling all sorts of equipment along a passenger train? These are much more complex than the functions needed for controlling locomotives in multiple.
Just for clarity, Locotrol is not for multiple working, which remains AAR standard, but for linking sets of locomotive spread up and down a train, at intervals among the wagons. It does transmit the AAR MU signals, in its own format. North American trains have become of such a size that, over undulating gradients and curves, pulled couplings and mid-train derailments occurred with 'pusher' locomotives, which started being placed inside the formation rather than at the rear end, whilst still being conventionally driven, with crew commands over the radio, and have advanced from there to now often having single locos spread at intervals. The pioneer Locotrol setups used a separate unit placed in a redundant classic 1950s passenger streamliner 'B unit', one of the ones without a cab, but they did of course have their AAR multiple connections to transmit commands to the set of locos they were controlling. Later the necessary equipment was placed inside the locos. As well as radio control from the front they integrate this with strain gauges in the couplers.
It uses a multiplex transmission for these over a couple of the otherwise spare wires in the standard system
Does AAR define the comms protocol for these cables, to the extent that passenger multiple units so fitted can interwork without restriction?
Thanks for the correction and information
I had a feeling that 150+170 combinations ran in Wales but I couldn't remember specifically. Thanks for the confirmation. I do recall 142/143+158 pairs running to Ebbw Vale sometimes.
I think it's down to software. There was a brief period when they could work together. I have travelled on a mixed pair. No idea why they became non-compatible again.
I can't remember if 150+170 (or anything+170) ran in passenger service in Wales, but the 170s' "legacy compatibility" was commonly used in 2021-2023 around mid-afternoon, to take the trains that had terminated at Cardiff Central from Fishguard and Ebbw Vale (I think) on Empty Coaching Stock moves from Cardiff Central to Canton depot as one train (clips merely "clipped" by me with YouTube's "clip" feature; all the videos they're from are by Sion's Train Videos:
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To be clear - ETCS needs to be fully isolated in all driving vehicles before the underframe can be accessed.
That is so ridiculous especially as they are brand new trains that were built at the same time. That is utter incompetence. I always thought that the only difference between the 730/0s and 730/2s was the amount of coaches and livery and seating. I wonder what exactly it is that prevents them from working together.
Between the 458/0 and 458/5 fleets the first problem was you couldn’t physically couple them. 458/0 had Tightlock couplers, 458/5 has Dellners.
Oh i forgot they had changed the couplers during the 458/0 to 458/5 conversion. I wonder what the point of that was when they can not couple to any other classes and work entirely with themselves.
The Tightlocks had to go to allow the level access through the gangway. The other benefit of Dellners is for emergency coupling to a Desiro to clear the line.
For as-was SWT 458/5s to be compatible with as-was SWT Desiros?
Mostly surrounded by Desiros with Dellners though. The change was to allow them to couple for rescue purposes
This has changed now with the new TCMS update: https://www.railforums.co.uk/threads/class-730-lnr-wmr-delivery-test-updates.215134/post-7328684 (quoted below)
About that...
Could you please advise what we are looking at in this photo? If nothing else, for those using screenreaders.
Very rare spot. Not seen that happen for a long time. I know the 375s and 376s and 377s occasionally couple to each other on empty stock workings but it is certainly very rare. The last time i saw it was over five years ago.
It is a 375 and a 376 coupled to each other on an empty stock working. Probably heading to or from one of the depots.
