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Post by elo10538 on Oct 21, 2014 9:24:34 GMT
Just a question that comes to mind regarding the use of wooden shoebeams on Underground Rolling Stock. Was the use of wood purely to insure for electrical isolation of the pos. shoes from the rest of the chassis/ bogie, or were they provided so that in case of problems they would break rather than derail the stock. I did wonder in relation to recent events, and then what was the wood that was actually used; presumably a hard wood but what sort.
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metman
Global Moderator
5056 05/12/1961-23/04/2012 RIP
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Post by metman on Oct 21, 2014 10:32:34 GMT
The early metropolitan railway electric saloon stock of 1904 had pick up shoes mounted on metal channels at the ends of the beams. These over turned the district railway juice rails and the cars were modified. Strangely the Metropolitans electric rails were unaffected! The 1904 Camel back locos also had the same arrangement initially. I'm not fully sure to the reasons of wood but your points do not seen unreasonable.  |
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Post by John Tuthill on Oct 21, 2014 11:32:18 GMT
Just a question that comes to mind regarding the use of wooden shoebeams on Underground Rolling Stock. Was the use of wood purely to insure for electrical isolation of the pos. shoes from the rest of the chassis/ bogie, or were they provided so that in case of problems they would break rather than derail the stock. I did wonder in relation to recent events, and then what was the wood that was actually used; presumably a hard wood but what sort. I remember reading years ago that Jarrah Wood from Australia was commonly used for sleepers. When seasoned it was literally 'rock hard' was water resistant and due to it's density was a low fire risk. Obviously concrete has now made it obsolete. |
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Post by tjw on Oct 21, 2014 16:10:06 GMT
Think of a material that...
1. Is a good insulator
2. Is cheap and easily available
3. Was available c. 1900
Wood springs instantly to mind, If I remember correctly at least some LT shoe beams were made of Teak, (strong, hard and resistant to water)
It is many years since we were restoring the Chesham set / Ashbury / Metropolitan carriages, but I think some of the Teak we used to repair / re-build, came from LT shoe beams.
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Post by phillw48 on Oct 21, 2014 16:57:12 GMT
Yes, it was teak but teak is now virtually impossible to obtain due to the moratorium on the export of tropical (rain forest) hardwoods. Finding suitable timbers for restoring teak bodied rolling stock has become a serious problem in recent years and any teak sleepers and shoe beams have been used up. Another source of teak has been chemistry lab tables as they can provide wider panels. A few years ago some teak trunks were discovered as deck cargo on a ship sunk during WW1. Despite being under the sea for 80+ years only the outer few inches had been attacked by teredo worms.
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Post by tjw on Oct 21, 2014 18:54:55 GMT
Teak can be found if you know where to look... When I was last working on timber framed carriages (5 years ago) we could still buy some sections, I note that restoration projects of teak panelled and framed carriages continue so presume that this is still the case.
The teak from the WW1 ship was great, we used one length to re-panel a GNR carriage really loverly stuff, I was told only the outer inch was not fit for use. Most of that Teak was used to repair HMS Victory.
Reminds me of around 15 years ago, I was looking for some second hand timber to replace some framework from an SECR brake carriage built 1910, my search took me to some framework from carriages that had been dumped in a muddy puddle some 10 year previously. Well included among the framework where 4 lengths of pullman carriage bottom rail approx 20' long by 6" x 4" solid teak! Well after removing the pins and other metalwork so I could run it through our wood working machines, I was left with plenty of excellent quality Teak (only the outside ?" was in anyway damaged).
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Post by elo10538 on Oct 22, 2014 12:25:34 GMT
Many thanks for all the info. Always wondered what wood was used, and guess some will on the lookout for a supply of some teak , of shoebeam dimensions. I presume shoebeams today are made of something completely different; a laminate or some type of high density plastic ?
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towerman
My status is now now widower
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Post by towerman on Oct 24, 2014 12:54:03 GMT
The blue paint given to the shoebeams on programme lift & heavy overhaul was also fire resistant.
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roythebus
Pleased to say the restoration of BEA coach MLL738 is as complete as it can be, now restoring MLL721
Posts: 1,275
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Post by roythebus on Oct 24, 2014 18:16:30 GMT
another purpose of wooden shoe beams was in case the shoe was damaged, there was a problem on the train line(the electric cable that used to run the length of the train carrying line volts) and the train needed to be isolated. It was supposed to be easy to cut a wooden shoe beam off, but then in the early days what else was around that was strong enough to do the job that would provide insulation?
The only time I had to cut shoe beams off (sorry for going a bit off-thread but relevant) was working a couple of 508s to Hampton Court one afternoon, pulled out of Earlsfield, lost the juice. Reset, got the juice, opened the handle, lost the juice. Start of the evening peak..big poopoo time. I went through the fault finding book, ended up getting assistance in the rear from another train. Coupled up, every time he took power, we lost the juice!
It couldn't be MY train, it had all the shoe fuses out. So the fitters from Wimbledon Park came over and we started cutting the shoe gear off with saws. Under one of the middle cabs was a coke can wedged between the shoe carrier and the bogie frame; every time the train moved, the shoe gear tilted slightly and caused a dead short!!
Total 3 hours delay and the Waterloo evening peak in chaos! What did I hear about it? Nothing, not even a request for a report!
Just to add to the fun, we had to run into Wimbledon to reverse into the depot. Arrival at Wimbledon was greeted with a cheer, the first train for 3 hours, yippee. Sorry folks, this train is the one that broke down!! The signalman wasn't happy, something like 25 lever pulls to get from the down local to the Up East Putney.
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