Uncompatibility of newer stock on other LU lines

I guess that the '67s and then '73s were the first to be specifically 'line' based?

(thinking TubE based!)

Couldn't the 73ts have worked on other lines?

Surely the economies of having the longer cars of the 73ts and 95ts, thus saving the need for the 7th car, are far in excess of the currently hypothetical problem of lack of stock standardisation.

Likewise, has the extra width of the A stock been worthwhile throughout its life? A definite yes, as the plans never envisaged a need for it to use the District.

The 95ts can be hauled along the Piccadilly line (as for delivery) - it is just that they haven't tested the AC traction motors etc for interference with the signalling and other systems as there hasn't been a need for the testing.

The new signalling systems on the Tubelines Lines would allow some interworking, with the 73ts replacement rumoured to be similar to the 95ts.

If anything the trains are becoming more compatible with the S stock coming!

96TS can only run under its' own power on the Northern Line,all transfers have to be done a unit at a time between battery locos,suspect this is due to signal interference issues.

Very true; I've often pondered about the root causes of non-compatibility and I almost always end up at the conclusion that there has been some form of risk analysis between AC motors/jointless track circuits/DC motors.

I think the risk analysis gives a (vanishingly) small potential of induced spikes - look at all the suppression work that needed to be done for the introduction of Eurostar services because of the AC traction motors IIRC; I think too that some of the work in the Farringdon/Moorgate area is suppression work.

Perhaps it is far easier to say: 'No, although the risk is small; it is safer to put a blanket ban down so there will be no malfunctions at all'?

Yes, but why should each line be run as a seperate entity (increasingly almost as a separate railway)?

Where's the benefit of such a fragmented approach rather than a common one?

In the District Line of old, up to the Q stock in 1938 (and indeed the Southern Railway up to the mid fifties) everything was made backwards-compatible, which made technical advances difficult and why there was still slam door stock running south of the Thames less than ten years ago.

The alternative is to optimise each batch of stock for the job it has to do. For example, the A stock (and incidentally the BR Class 165 Networker Turbos) were built up to the more generous GCR and GWR loading gauges, which limits them to the lines they were built for but is to the benefit of the people who use them.

Now the answer to your questions very much depends on your viewpoint.

From an LU operating perspective, running each line fragmented rather than commonly makes absolute complete sense.

Each line has it's own unique points - the Piccadilly line has Heathrow, whilst the Waterloo & City is a short hop commuter only line, for example. The District line sees a lot more tourists than the Metropolitan line to give another.

All those types of differences (I'm sure I could bore you to death if I went into great detail with each line) do dictate the different types of stock that suit each line. Of course loading gauge also plays a large part in the type of stock too.

Now you can only train drivers on so many different routes & stocks, as they have to complete annual refreshers etc - and they have to be managed in a sensible manner, particularly once special working comes into play (engineering works to you) as well as in terms of line specific team talks, performance reviews, etc, etc. A balance has to be struck such that their usefulness (ie, time spent actually driving a train) is maximised & cost effective.

Then there's the service control perspective. Yes plans are in place to merge all the sub surface lines (Circle, District, H&C and Met) into one control centre, but surely it is generally sensible that you have one control room per line? If you have one control room per line, the service control function can then work far more effectively towards the specific requirements that line has when compared with another.

Having line specific grades then means there is an effective line based management structure, all geared to that lines specific requirements.

It's all about local staff with local knowledge that are aware of local issues.

There is a generic combine wide control centre, as indeed there are combine wide departments and management, but their job is to maintain the overall big picture. You can't have people doing both line based and combine wide work simultaneously as that just wouldn't work effectively.

Not sure of the present scenario, but there were certainly individual interlockings until quite late on, some may in vestigial form survive.

Well on the subject of the sainted 'A's, a reasonable amount were provided for the initial timetable. Its just things went downhill rather rapidly. I did once hear a story from a motorman that enough A stock was ordered to cover the entire local route to Aylesbury, if it were ever needed. Who can say!

I suppose London has leeway in that a few lines are reasonably self contained. Northern, Central, W&C, Vic, Jubilee to an extent, so there is a decent choice between business unit and combine.

Yes, but that couldn't really happen as to replace every train on every line at the same time would take, I guess 20 years?
So each 'franchised' line would pay for their trains when they got them, thus staggering the cost.

If all the lines had the same stock - with body variations for line - I'm thinking rolling chassis here, so that the cab and train controls were universal, then that would make inter-line transfers of staff easier and a reduction in cost because you have the power of bulk-buying your consumables and spare parts.

Has there been photographic evidence of Standard stock on the ELL? ISTR that it might have been cleared to run out as far as Little Ilford, but I can't remember where or how I read this?

I'm sure the Standard stock ran on the Victoria Line in the test stages - or did the 67ts run on the Northern City?

I have in my hot little hand,a 1977 edition of "London Underground Rolling Stock" by Brian Hardy,and there,on p.79,is a picture of Ballast Motor L74 converted from a 1923 Standard Stock DM,at Northumberland Park.
I suspect they went absolutely everywhere,in this format.

The concept of a "Standard" stock makes most sense when you have a central overhaul depot serving all lines.Economies of scale result as the overhaul scheme moves seamlessly from one line's stock to the next.
Now that it seems that lines maintain their own stock,this is less of a factor;instead the pressure is for each line to have its own stock,with little reference to what other lines are using.