Dufus Posted March 27, 2017 Share Posted March 27, 2017 Hi All, I need some advice please. I am building a OO layout which includes a girder bridge on a curve. Today I have been trying to run a couple of trains around the curve to measure what clearance I need on the passenger carriages and with various goods trucks. I have the track all set up on the baseboard with the inclines in place and have been able to test that my locos can manage the slope under a full load. All this went OK with my little goods loco. When I went to test the Flying Scotsman it would run for a few inches then the light went out on the controller and I had to unplug everything before power would restore. I am using the Hornby DC power supply as supplied with the Scotsman set. I intend to convert to DCC with a Gaugemaster set that my daughter gave me for Christmas but not until things are set up. My plan is to use the DC controller to test the track first. I have found that the loco will work fine when running solo without the tender. I can put the tender on the track without attaching it and it still runs fine. The moment I attach the tender to the back of the loco every thing stops. I can see two wires that connect the two on the top of the pin and there are two contacts that attach to the pin below the hole. They appear to connect in the correct places. I obviously don't want to convert this loco until I have resolved this issue. Any advice please? Can I run the loco just using the pickups on the loco, if so what is the best way of isolating the tender? Link to post Share on other sites More sharing options...
Theakerr Posted March 27, 2017 Share Posted March 27, 2017 The first question has to be are you putting the plug in backwards? In theory there is a small detente that is supposed tog tee that the plug only goes in one way but i have seen examples of where it will go in both ways. you can check this with a volt meter with power to the track. Next possibility and also seen is that somewhere the wires are shorting across each other but only do it when the plug is put in because the ends of the plug touch and push the connectors into each other. Link to post Share on other sites More sharing options...
DCB Posted March 28, 2017 Share Posted March 28, 2017 Something is shorting, possibly the wires on the tender are reversed. Personally I would just strip out the tender pick ups as I can't see any need for them. Link to post Share on other sites More sharing options...
RMweb Gold Dunsignalling Posted March 28, 2017 RMweb Gold Share Posted March 28, 2017 (edited) Hi All, I need some advice please. I am building a OO layout which includes a girder bridge on a curve. Today I have been trying to run a couple of trains around the curve to measure what clearance I need on the passenger carriages and with various goods trucks. I have the track all set up on the baseboard with the inclines in place and have been able to test that my locos can manage the slope under a full load. All this went OK with my little goods loco. When I went to test the Flying Scotsman it would run for a few inches then the light went out on the controller and I had to unplug everything before power would restore. I am using the Hornby DC power supply as supplied with the Scotsman set. I intend to convert to DCC with a Gaugemaster set that my daughter gave me for Christmas but not until things are set up. My plan is to use the DC controller to test the track first. I have found that the loco will work fine when running solo without the tender. I can put the tender on the track without attaching it and it still runs fine. The moment I attach the tender to the back of the loco every thing stops. I can see two wires that connect the two on the top of the pin and there are two contacts that attach to the pin below the hole. They appear to connect in the correct places. I obviously don't want to convert this loco until I have resolved this issue.. Any advice please? Can I run the loco just using the pickups on the loco, if so what is the best way of isolating the tender? It sounds like your loco is the older type that can be separated from it's tender without unplugging a lead. If so, the probability is that the contact on the loco has got bent and is touching something it shouldn't on the tender. There should be a view of it on the service sheet which will give some idea of what shape it should be. John Edited March 28, 2017 by Dunsignalling Link to post Share on other sites More sharing options...
RMweb Premium kevinlms Posted March 28, 2017 RMweb Premium Share Posted March 28, 2017 Something is shorting, possibly the wires on the tender are reversed. Personally I would just strip out the tender pick ups as I can't see any need for them. I think an investigation into the cause is worth the time before ripping things out. Link to post Share on other sites More sharing options...
bike2steam Posted March 28, 2017 Share Posted March 28, 2017 It sounds like your loco is the older type that can be separated from it's tender without unplugging a lead. If so, the probability is that the contact on the loco has got bent and is touching something it shouldn't on the tender. There should be a view of it on the service sheet which will give some idea of what shape it should be. John I agree, the most common fault being the two upper thin contacts can bend easy, and contact where they shouldn't, namely the centre pin, one of the reasons I permanently couple, and wire the loco, and tender. 1 Link to post Share on other sites More sharing options...
Dufus Posted March 28, 2017 Author Share Posted March 28, 2017 Thanks guys, The contacts don't appear to be bent but something is obviously shorting. I have found my multi meter in the shed so I'll start probing. I like the idea of permanently wiring the two together, they will always be run together and this will stop this kind of thing happening again. I think the tender will be coming apart this weekend and I'll work from there. Thanks for all your suggestions. I'll let you know what happens. Chris Link to post Share on other sites More sharing options...
34theletterbetweenB&D Posted March 28, 2017 Share Posted March 28, 2017 A quick and easy test is to remove the loco to tender link with the contacts on it, and make a temporary replacement drawbar from a piece of plastic and hitch on the tender; then see if the shorting problem is eliminated. In which case permanent soldered wire connections, and a more permanent drawbar, and you are done. But what if the shorting is still present with the temporary drawbar attaching the tender? There is a lurking problem in versions of the Hornby Gresley pacific (and other's!) model mechanisms, which is that the loco's chassis block is live to one rail. That can lead to shorting on the loco. You might think you have covered that as the loco alone is not showing the shorting problem, but its dynamics when moving are altered by having a trailing load. It's usually a side rod live to the chassis block contacting a wheel rim or axle end when this problem arises; watching the loco running in the dark will show the location with a small spark should this problem be present. Link to post Share on other sites More sharing options...
DCB Posted March 28, 2017 Share Posted March 28, 2017 If you change the tender wiring or draw bar take the time to close couple the tender it is probably the easiest and most effective way to improve Rtr locos .About 3mm gap between back of cab and tender front works for most Pacifics on 2nd Radius curves. Most Rtr stuff has enough clearance for 13.5" curves and the fireman would need to be an olympic athlete to jump the gap when firing. Link to post Share on other sites More sharing options...
micklner Posted March 28, 2017 Share Posted March 28, 2017 I have had secondhand Tenders that have been wired the wrong way around for the Loco. As said before A3's and other pacifics do not need Tender pick ups just cut the wires off. Link to post Share on other sites More sharing options...
RAF96 Posted March 28, 2017 Share Posted March 28, 2017 The Hornby springy finger loco to tender drawbar works like this: The clamp arrangement grips the metal tender post and the two fingers should be horizontal athwartships but bent up a tad to bear on the metal plate the tender post is attached to. If the fingers are distorted they can short on the post in a tight curve or if the track is bumpy fore and aft then the clamp can short on the plate part. Either way gets you a short and the controller calls it a day. An insulating washer on the post can help but the fingers need to be over it. I stripped off the contacts from my drawbar and rigged the wires to a 4-pin plug/socket (you only need two pins on a standard rig but I needed two speaker wires as well). The bare drawbar still uses the tender post to pull on but doesn't transmit electrical power across the gap any longer. Rob Link to post Share on other sites More sharing options...
Dufus Posted January 28, 2018 Author Share Posted January 28, 2018 Just realised I never did finish this off. I stripped the tender down and found one of the pickups was not seated properly. It did not look like it should have been causing a short but when I reassembled all worked fine. I have since converted the loco to DCC and it runs like a dream. Thanks for your advice. Since posting this query I have been given a couple of very old non-runner locos that I have had the confidence to strip and clean and get running again. Many thanks for all the advice, it has given me a lot more confidence in stripping engines down. Chris 2 Link to post Share on other sites More sharing options...
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