RMweb Gold The Johnster Posted May 10, 2017 RMweb Gold Share Posted May 10, 2017 Our hapless soul would have been perfectly sate looking upwards in them, as there was no third rail for safety reasons. Mostly colliery sidings in the Kent coalfield I believe, and made obsolete by the introduction of the E6000 Electro-Diesels, which nowadays would be called 'Bi Mode'... Ok, how do you tow a dead diesel hydraulic? If the hydraulic pump is not working, which it isn't because the diesel is shut down and not powering it, then there is no pressure in the hydraulic system, and the final drive units can be disconnected, leaving the dead loco as a free-rolling vehicle. Simples, as the meerkat says... Link to post Share on other sites More sharing options...
stewartingram Posted May 10, 2017 Share Posted May 10, 2017 I had to do the "3rd rail course" when a Traction Trainee, (remember them) at Kings Cross, for the 3rd rail into Moorgate and going across the North London Line. As well as having it drummed into us, "watch were you step" when getting off a loco, we had to go down to Drayton Park station where a short section of 3rd rail track (not live) had been set up so we could show off our prowess with a short circuiting bar. Simples in those days. Paul J. Sometime within the past 10 years or so, I did mine just behind the Necropolis station at Waterloo. The instructor demonstrated the s/c bar, on the old siding there, which was still live. Stewart Link to post Share on other sites More sharing options...
RMweb Premium New Haven Neil Posted May 10, 2017 RMweb Premium Share Posted May 10, 2017 Um. There could still be residual magnetism in the motor field pole pieces, which when driven at speed could possibly self generate. To be really safe you should withdraw the brush gear. Hydraulics depend upon the system IIRC, some you had to disengage cardan shafts? Link to post Share on other sites More sharing options...
Grumbleweed Posted May 10, 2017 Share Posted May 10, 2017 Ok, how do you tow a dead diesel hydraulic? Carefully? Link to post Share on other sites More sharing options...
mervyn Posted May 10, 2017 Share Posted May 10, 2017 no motor contactors in no circuit..did have a 31 towed on the shed once with motor contacter stuck in wasn't a pretty sight in the electrical cubicle !! Hydraulics assume are the same as DMUs put final drive in neutral and they will freewheel? Link to post Share on other sites More sharing options...
modfather Posted May 10, 2017 Share Posted May 10, 2017 If your fluid flywheel isn't filled you won't transmit power back? Link to post Share on other sites More sharing options...
jim.snowdon Posted May 10, 2017 Share Posted May 10, 2017 Um. There could still be residual magnetism in the motor field pole pieces, which when driven at speed could possibly self generate. To be really safe you should withdraw the brush gear. Not sufficiently to worry about. In practice, the effect even when the motors are connected, as in rheostatic braking on electric stock, is so small that no meaning effect results. The traction equipment on LUL stock that had rheostatic braking was provided with a field injection circuit, whose purpose was to give the traction motor fields an initial excitation, after which the field would build up as the (braking) current rose. Jim Link to post Share on other sites More sharing options...
Swindon 123 Posted May 11, 2017 Share Posted May 11, 2017 no motor contactors in no circuit..did have a 31 towed on the shed once with motor contacter stuck in wasn't a pretty sight in the electrical cubicle !! Hydraulics assume are the same as DMUs put final drive in neutral and they will freewheel? Same principle is used when towing certain diesel mechanical shunters, such as Class 03 and 04 where the final drive could be isolated as on a DMU. Hunslet 0-6-0 class 05's and the 0-4-0 version had a Neutral position on the final drive gearbox, and could easily be towed in that position. This may also apply to the Ruston 0-4-0 pair, D2957/8 as they had Hunslet 4 speed gearboxes as well, similar to the 05's. The Hudswell Clarke 0-6-0 shunters D2500-19 (SSS Powerflow final drives), and Andrew Barclay D2400-9, (which had a Wiseman type 15 RLGB final drive), had to have the connecting rods from the final drive to the driving wheels removed, except when towed at "Dead Slow" speeds. I'm not 100% sure about class 01 and 06, but as they had the same final drive as D2400-9, they may also have had to have connecting rods removed. Paul J. Link to post Share on other sites More sharing options...
Edwin_m Posted May 11, 2017 Share Posted May 11, 2017 (edited) Permanent magnet motors seem to be the latest thing on the big railway, with rare earth magnets being powerful enough to provide the field on a traction motor. I don't know what happens when trying to tow one of those! http://www.railwaygazette.com/news/traction-rolling-stock/single-view/view/permanent-magnet-motors.html Edited May 11, 2017 by Edwin_m Link to post Share on other sites More sharing options...
RMweb Gold PhilH Posted May 11, 2017 Author RMweb Gold Share Posted May 11, 2017 If your fluid flywheel isn't filled you won't transmit power back? It's a b*gg*r when your fluid flywheel isn't filled. Link to post Share on other sites More sharing options...
modfather Posted May 13, 2017 Share Posted May 13, 2017 It's a b*gg*r when your fluid flywheel isn't filled. Usually standstill valve or a knackered selector on a Voith - or someone messing with the air regulator. Link to post Share on other sites More sharing options...
Trog Posted May 17, 2017 Share Posted May 17, 2017 Funny you should say that...when out on the mainline with various locos the one thing that really, and I do mean really, concentrates and exercises my mind is when I have to step over the third rail. Obviously we look for a break in it to cross but sometimes you have no choice. Again, although we have the 3rd rail guards which fit over it, when you have to water with the hose(s) just above it that makes you think hard too. It is interesting how the railway divides into two on third rail those who have not worked with it or work in H&S who think it is deadly and treat it with the caution due an angry rattle snake. Or those who have worked with it for years and while somewhat respectful of it particularly in wet weather think it is nothing to be excited about. Would be somewhat frowned upon these days but I knew of staff who used to sit on the con rail to eat their sandwiches as it was a more comfortable height than the running rail. Link to post Share on other sites More sharing options...
101 Posted May 17, 2017 Share Posted May 17, 2017 (edited) It is interesting how the railway divides into two on third rail those who have not worked with it or work in H&S who think it is deadly and treat it with the caution due an angry rattle snake. Or those who have worked with it for years and while somewhat respectful of it particularly in wet weather think it is nothing to be excited about. Would be somewhat frowned upon these days but I knew of staff who used to sit on the con rail to eat their sandwiches as it was a more comfortable height than the running rail. I've not worked on the third rail for many years, but you could always (and probably still can) tell the southern region men from the 'foreigners' by the greatly exaggerated steps we took over the third rail as you say those used to it didn't seem to care and I myself have witnessed p way staff standing it on several occasions! Edited May 17, 2017 by 101 Link to post Share on other sites More sharing options...
RMweb Gold big jim Posted May 18, 2017 RMweb Gold Share Posted May 18, 2017 I've not worked on the third rail for many years, but you could always (and probably still can) tell the southern region men from the 'foreigners' by the greatly exaggerated steps we took over the third rail Link to post Share on other sites More sharing options...
101 Posted May 18, 2017 Share Posted May 18, 2017 I've not worked on the third rail for many years, but you could always (and probably still can) tell the southern region men from the 'foreigners' by the greatly exaggerated steps we took over the third rail That's about right Link to post Share on other sites More sharing options...
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