towerman
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Post by towerman on Oct 31, 2014 13:59:59 GMT
In the early 70s The Victoria Line did an experiment to check brake block wear by having every train except two run around for a month with the rheo brake cut out.You should've seen the build up of dust on the platforms & tiling in just that short time.Mind you I never understood why LT stopped using the Ferrodo VG10 block with the introduction of the 67TS and started using TBL blocks,they were horrible,painted black & very prone to cracking across after a couple of weeks.LUL still uses TBLs but now painted grey.The original black TBLs were very soft & if they didn't crack across after a couple of weeks'if the rheo on the train wasn't working the blocks would only last 3 weeks to a month.
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Post by domh245 on Oct 31, 2014 15:15:53 GMT
Out of interest, does (did) any stock use disk brakes? I know they are the favoured brakes on network rail, but the 700s are going to have tread brakes to save weight, and scrubbing the wheels, so I can't imagine if any stock did have discs fitted.
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towerman
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Post by towerman on Oct 31, 2014 15:31:59 GMT
As far as I know 72TS motor car 3330 had discs(on one truck)as a trial right up to scrapping,the staff hated them,were a right b****r to get at.Also they worked on the inside of the wheel unlike mainline stock.
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Post by brigham on Oct 31, 2014 17:58:07 GMT
Do railway disc brakes only work on one face of the wheel? I hadn't realized that, although from what I've seen, the Ferodo material (the 'meat') is on the disc, rather than the pad.
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towerman
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Post by towerman on Nov 7, 2014 13:55:24 GMT
There was a pad which worked against a metal disc but was fitted between the motor & the wheel hence being very awkward to get at.
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Post by John Tuthill on Nov 7, 2014 15:46:41 GMT
There was a pad which worked against a metal disc but was fitted between the motor & the wheel hence being very awkward to get at. I remember the 'S' type Jag was a pain, as it had inboard brakes!
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Post by patstonuk on Nov 7, 2014 19:53:53 GMT
Out of interest, does (did) any stock use disk brakes? I know they are the favoured brakes on network rail, but the 700s are going to have tread brakes to save weight, and scrubbing the wheels, so I can't imagine if any stock did have discs fitted. The 700s will have a mix of brake types - with tread brakes on the powered bogies and disc brakes on unpowered. Apart from the advantage of tread brakes in 'conditioning' the tread, improving adhesion, this arrangement is necessary because of lack of space for disc brakes on these bogies. This is a shot I took when the 700 mock-up was exhibited at the ExCeL last January - the tread brakes are clearly visible. Apologies for going OT.
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Post by Deleted on Nov 10, 2014 21:41:21 GMT
Was this an early money saving idea by the London Transport? (Which turned out to be false economy, as the labour cost of changing brake blocks ten times a year on the Victoria Line far exceeded the modest savings of the budget brake pads.
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towerman
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Post by towerman on Nov 14, 2014 13:53:32 GMT
Don't really know,was probably down to cost the TBLs were cheaper.
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DWS
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Post by DWS on Nov 14, 2014 14:16:30 GMT
Don't really know,was probably down to cost the TBLs were cheaper. Towerman what does TBL stand for ?
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towerman
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Post by towerman on Nov 21, 2014 13:48:28 GMT
Something Brakes Ltd?
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Post by 100andthirty on Nov 29, 2014 17:25:13 GMT
Back to the thread.......the old 1986 tube stock blue train was fitted with disc brakes. This train had steering bogies and there was nowhere to mount the tread brakes on the steering frame. As the steering mechanism included the nose suspended/axle hung motor there was nowhere on the axle either. Hence the disc was on the opposite end of the motor shaft to the drive pinion. The speed of the disc was high by the standards of the day (as it was running at motor speed, not axle speed) and the friction material suffered from brake fade. This was one reason why the only two cars of the blue train were run in service with four cars of the red or green trains. In conversation with a brake pad material supplier a few years after the train was withdrawn I was informed that the brake fade problem would have been solved as a result of rapid development of friction material for high speed trains.
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Post by norbitonflyer on Nov 29, 2014 18:19:13 GMT
the only two cars of the blue train were run in service with four cars of the red or green trains. . There were, surely, two two-car units of each train, so there were four cars of the blue train as there were for the red and green ones. I have seen photos and video footage of various six-car formations, but none of them except the static display at Woodford show all four blue cars in the same train - always blue with two green, or two red, or one of each.
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