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Post by ruislip on Apr 15, 2008 3:45:38 GMT
Did anyone within LT realise that it would last as long as it has? If not, what was the life-span that was projected for it?
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Deleted
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Post by Deleted on Apr 15, 2008 9:52:12 GMT
I have never seen anything documenting an expected life-span for Underground stock, although I have seen a suggestion that 15-20 years was regarded as normal for a bus. Doubtless those who designed the A stock wanted to produce a quality product: that was the LT philosophy then.
Previous replacements of Underground stock (both surface and tube) came about largely because the previous stock was obsolete. The Met's T stock (and its loco-hauled equivalents) was well past its use-by date when it was replaced by A stock. Similarly, there was an obvious need to replace the Standard tube stock with stock that had all its equipment under the cars.
And on the roads, there was a definite need to replace the trams with RT buses, and later a perceived need to replace trolleybuses with RM buses.
But from the 60s to the 90s, there were no radical changes in transport technology. So there was no urgent need to replace the A stock, or the Vic line stock, or the RM bus. If they are properly looked after, there is no reason why PSVs (rail or road) cannot last for a very long time.
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Post by tubeprune on Apr 15, 2008 12:23:23 GMT
Railway Company accounts tended to show what the expected "book life" of a train is. The capital cost of buying the train is depreciated over the expected "economic" life of the train. In one case I remember seeing the "book life" of the Metropolitan Railway's stock as 36 years. The worst of it lasted less, the best lasted longer. My advice (FWIW  to a designer today would be to build a train with a 40 year structural life and a 20 year equipment life. The pace of modern technology shows that trains could economically be re-equipped with new traction kit and interiors after 20 years. |
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Post by johnb on Apr 15, 2008 12:48:13 GMT
But from the 60s to the 90s, there were no radical changes in transport technology Well, apart from AC traction and ATO... |
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Post by Deleted on Apr 16, 2008 1:21:08 GMT
But from the 60s to the 90s, there were no radical changes in transport technology Well, apart from AC traction and ATO... Well, LT could hardly adopt AC traction, and the expense of ATO on existing lines was considered to great to be worthwhile. |
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Post by johnb on Apr 16, 2008 11:45:09 GMT
Well, apart from AC traction and ATO... Well, LT could hardly adopt AC traction, and the expense of ATO on existing lines was considered to great to be worthwhile. Err, from the 95/96 stock onwards all new LU stock has and will have AC traction (barring surprising technological developments), and ATO is now being added to all lines which is precisely why the D stock is being retired so young... |
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Deleted
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Post by Deleted on Apr 16, 2008 17:41:17 GMT
think about the 1938 stock
they were on LT for 50 years and you could still find a trailer of 38 stock in 1994
and they are on the IOW and are 70 years, I bet LT never predicted they would last that long
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Deleted
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Post by Deleted on Apr 16, 2008 18:37:06 GMT
1938 stock and A stock were overhauled on a regular basis that meant they were given good preventative maintenance as well as between overhauls. Look after the machines properly and they will last a long time.
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metman
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Post by metman on Apr 16, 2008 23:27:43 GMT
They are an excellent design too! I believe the A60 stock was designed under 'Joe' Manser- what a legend!
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Deleted
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Post by Deleted on Apr 17, 2008 9:43:52 GMT
Well, LT could hardly adopt AC traction, and the expense of ATO on existing lines was considered to great to be worthwhile. Err, from the 95/96 stock onwards all new LU stock has and will have AC traction (barring surprising technological developments), and ATO is now being added to all lines which is precisely why the D stock is being retired so young... I thought your original comment referred to AC power supply. And my comment was that there were no radical changes in technology from the 60s to the 90s, by which I actually meant the early 90s. I agree that the advent of thyristor technology meant that there was a technological reason for introducing the 95/96 stock. |
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Post by ruislip on Apr 23, 2008 20:49:01 GMT
Look after the machines properly and they will last a long time. To use an example from aviation, consider the KC-135 tankers used by the USAF that were derived from the Boeing 707 commercial jet. Many KC-135s have been well-maintained by the USAF; while the 707 has been long, long retired from commercial use. |
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Post by edb on Apr 30, 2008 19:33:39 GMT
Look after the machines properly and they will last a long time. To use an example from aviation, consider the KC-135 tankers used by the USAF that were derived from the Boeing 707 commercial jet. Many KC-135s have been well-maintained by the USAF; while the 707 has been long, long retired from commercial use. Dare i mention the Nimrod or especially the Canberra |
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Post by astock5000 on Apr 30, 2008 20:32:42 GMT
They are an excellent design too! I agree with you metman, they are excellent. |
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Oracle
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RIP 2012
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Post by Oracle on Apr 30, 2008 21:38:48 GMT
There are still some 707s commercially flying plus John Travolta has a 707-138B. However there are military 707s still very much in active service. Who knows when the B-52H will finally retire? Talk was at one stage of 50 years' service!
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metman
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Post by metman on Apr 30, 2008 21:41:52 GMT
The B52s have outlasted what they were designed for even! Who carpet bombs anymore?
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Ben
fotopic... whats that?
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Post by Ben on May 1, 2008 13:24:58 GMT
Not carpet bombing...to quote William Shatner from 'Airplane! 2'; "Thats exactly[/] what they'll be expecting..."
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to a designer today would be to build a train with a 40 year structural life and a 20 year equipment life. The pace of modern technology shows that trains could economically be re-equipped with new traction kit and interiors after 20 years.
