Future of the Bakerloo Line?

I suppose these days a class 73 could be used for main line haulage over the DC to Euston, or a class 92?

No and no.

The traction power supply is incapable of such loads.

I suspect that comes down to what one determines is a tram and what is not.

These cars are based on the German Stadtbahnwagen type B design, which in practice as utilised by different operators in different towns in different countries can be found on metro or tram or mixed networks.

It is not worth trying to literally translate the term Stadtbahnwagen either as it will not yield anything meaningful; the common equivalent term is "light rail car" - which you won't get from a literal translation.

The two other systems I have travelled with similar cars are the Frankfurt U-bahn (Class U2 cars), and the San Diego "trolley" Blue line (the original 1980s cars).

Trainspotters see the term U-bahn => Frankfurt is a Metro.

San Diego street running => tram (= trolley in Americanese).

Yet they are the same vehicles with local customisations.

I do not think it is wholly wrong to refer to the Tyne Metro Cammell cars as tram derived just someone looking at them from another view.

With the benefit of hindsight, which is always 20:20 vision, I do wish I had done one of those diversions. Eons ago, there was IIRC a Sunday morning when a couple of day trains took the route in the Down direction, 47 hauled. Do rue not doing one of those. Ohh to have a Tardis, but then again if we did, there would be a lot of other things to go for.

SEG did try and get a 73 over the route, but it was like trying to get through a Swiss cheese by existing tunnels only. Most of it was practical in most places, but however we looked at it, all of it was not possible everywhere, and one mitigation to overcome one blocking point merely created another one elsewhere. For example, 73 on electric on a 4TC possible, 8TC not, led to run on diesel, but that insufficient power for the Primrose Hill DC tunnel grades even on a 4TC; then 2x73 too long; then the SEG trick of split the train (i.e. 73+TC + TC+73 in 2 portions) as we did on the DEMU over tracks still left other problems which I forget what it was; then there were droplight clearance issues (which no-one was bothered about when a Cig went to Watford but seemed to bother them with a TC; and then the 73 on diesel can't heat the train came up - which has the more important issue of float battery charge and after 30 mins lose things like AWS and taillights on the TC. And so on.

But the Bakerloo has actually more problems than the Picc. Older signaling, much more curved track in tunnel sections, an annoying single ended little depot, with the other depot, being no better than just a set sidings. E&C sidings requiring proper walkways to become usable again. And so the list goes on. It really is a marvel that line and the 72 stock are still running at all to be honest!

East end of Picc was resignalled in the 80s.

Signalling on the Underground is a bit like “Triggers “ Broom 🧹

With regard the point of assets (including signalling) reaching the end of its useable life, I would note that a significant factor defining the "life" of the system is the support of the electronic systems (which generally involve microprocessors and software languages) which soon become superseded so that alterations, spares and repairs become harder or become prohibitively expensive (particularly if you are tied to an exertnal supplier).
Examples of this for the Bakerloo line that I believe are already being addressed are the signalling control computers, Jointless track circuits.

This debate reminded me of this well known phrase
"the more they overthink the plumbing, the easier it is to stop up the drains..."

Sadly most of the the world is hell bent on dissapearing down a digital rabbit hole. Adding digital controls has its place in rail safety, but it must be matched by robust engineering, and thorough scrutiny of software is every bit as important.

Meantime even base model EVs are increasingly kitted out with so many extras - things which are doubtless considered highly unlikely to go wrong but sods law seems to garantee it will happen eventually.

Hence we should be taking great care to ensure anything people lives depend on - like digital fly by wire systems or self driving vehicles are not prone to deliberate or accidental failure. We must not overlook the basics - personally I do not think brand new planes should have pieces falling off, likewise couplings on mainline or tube rolling stock should not have been value engineered to the point where they are cracking up and failing in normal use.

A special meeting of the TfL Finance Committee held on 22 December 2023 was advised that a new agreement with Siemens revises the delivery profile of the new Piccadilly trains. link It is unclear what changes will be applied since the current milestones will remain unchanged: trials in London; entry to service; 27tph service upgrade. Early in Covid, depot works were postponed 6-months and this has not been made up. Also, Government funding is lower than expected. Perhaps volume production will commence later to avoid off-line train storage, allowing more train assembly to be done in UK. It mentions that this could reduce the gap to the start of production for the Bakerloo line option in the contract, funding for which will continue to be sought from Government in the coming year.

Surely the Bakerloo extension south of Elephant and Castle must hold some sort of record in terms of how long it’s been proposed for? It’s been talked about since at least the 1940’s!

As superteacher brought it up, Jago Hazzard did a great video on the 26 attempts to extend the Bakerloo. Hopefully, no.26 will happen!

(I’m aware this thread is about the future of the Bakerloo line.)

The only was that could work would be to create 24/7 bus lanes along already congested roads, as has happened on the approach to Gants Hill on SL2. Voters beware the things you aren't told about when you vote!!