SamES Posted November 29, 2012 Share Posted November 29, 2012 My first post. Hello all. I am attempting to convert an R239 Class 4P to DCC. I have installed an R8249 decoder and the loco runs fine on straight and curved track. However, when crossing points in the turnout direction, it stops when going slowly or hesitates when going faster. Also, the select controller I am using resets/reboots and goes back to address 3. It appears that the wheel crossing the frog is shorting the rails. I have compared the wheels with a modern Hornby DCC loco and the wheels on the R239 are wider. Is this the problem or am I barking up the wrong tree? Regards Link to comment Share on other sites More sharing options...
poliss Posted November 29, 2012 Share Posted November 29, 2012 If you can adjust the distance between the wheels to 14.4mm it should help. Link to comment Share on other sites More sharing options...
SamES Posted November 30, 2012 Author Share Posted November 30, 2012 poliss said: If you can adjust the distance between the wheels to 14.4mm it should help. Hello Poliss. Have measured distance between wheels and they are all just over 14mm. Problem occurs when large wheels are passing over frogs. Bogie wheels pass over with no problems. Thanks for the reply. Did the Hornby wheel spec change at some point to better work with DCC or accomodate tighter spacing of live rails across frogs? Regards Link to comment Share on other sites More sharing options...
poliss Posted November 30, 2012 Share Posted November 30, 2012 The only difference between DC and DCC is the decoder in the loco. No other standards have changed. Link to comment Share on other sites More sharing options...
SamES Posted November 30, 2012 Author Share Posted November 30, 2012 poliss said: The only difference between DC and DCC is the decoder in the loco. No other standards have changed. Link to comment Share on other sites More sharing options...
SamES Posted November 30, 2012 Author Share Posted November 30, 2012 SamES said: poliss said: The only difference between DC and DCC is the decoder in the loco. No other standards have changed. Hello again Poliss. Will check the wheel spacing again just to make sure. How would I go about adjusting the spacing? It's somthing on our Class 4P loco because we run three locos on the layout and only have a problem with the class 4P. Will carry on with the investigation! Thanks Link to comment Share on other sites More sharing options...
poliss Posted November 30, 2012 Share Posted November 30, 2012 When you say wider wheels do you mean wider tyres? Older locos did have wider tyres and deeper flanges which could cause shorting as they go over points. It's also possible that deeper flanges could lift the loco as it goes through points. If it's just shorting because the wheel tyres are touching the other rail as the loco goes over the points, the problem can be solved by using insulated rail joiners on the 'v' exit rails from the points. You will need to add power feeders on the rails beyond the points if insulated rail joiners are fitted. Link to comment Share on other sites More sharing options...
morairamike Posted December 1, 2012 Share Posted December 1, 2012 Waht age is this loco, looking on the web it appears to be of an earlier era. I recall that in the early years that locos had deeper flanges and that the centre drive wheel was flange less to allow it to go around the then available curves. You say that other locos run well on your layout, what era are they? If you are using Hornby set track then the points are insulafrog and the problem will be due to the wheels not touching the track, look at the frog, and the wheels, when the wheels are on the frog have they lifted off the track? If yes then the plastic on the frog under the flange needs to be reduced or the wheels replaced with new wheels. Attempting to move older wheels on axles is not as easy are the modern ones. Check also the pickups on the wheels and if needs be adjust. If the wheels don't lift then try a stay alive decoder. Link to comment Share on other sites More sharing options...
The son of Triangman Posted December 1, 2012 Share Posted December 1, 2012 Flanges on these earlier locos shouldn't be a problem, the wheel standards haven't really changed that much. Hornby points in recent years seem to have gained more shallow flangeways. The loco was made in the time period 1992 - 1997 so shouldn't be a problem unless there is something wrong with the loco. Hornby locos made after 1973 should run on modern track as a rule. Link to comment Share on other sites More sharing options...
SamES Posted December 1, 2012 Author Share Posted December 1, 2012 Hello again Poliss. I meant wider tyres. The loco is an older one. Have checked with a meter now and problem is definately the large/driving wheels shorting the rails as they go over the narrow part of the frog on points. The centre driving wheels have rubber tyres and did have larger flanges on the inside edge compared to the outside edge. I thought this was the problem and reduced the inside flanges to the same size as the outside. This partly solved the problem. Loco now goes over single points but stops when running over two points, one after the other. Don't know anything about insulated rail joiners and power feeds but will look into it. We are using Hornby 8072/3 points with DCC clips. My thought at the moment is to look into the feasability of changing the wheels! Thanks for the help. Regards Link to comment Share on other sites More sharing options...
SamES Posted December 1, 2012 Author Share Posted December 1, 2012 [reply]morairamike said: Thanks morairamike. Other locos are a Lima class 33 of 1970s vintage and a Hornby 0-4-0 tank bought last year. I am looking into replacing the wheels. Thanks for the info. Regards Link to comment Share on other sites More sharing options...
Gregd99 Posted December 1, 2012 Share Posted December 1, 2012 btw..... did it run properly on dcc before the conversion? if not, then this is always a good thing to check. Link to comment Share on other sites More sharing options...
The son of Triangman Posted December 2, 2012 Share Posted December 2, 2012 Strange! I have the same loco but R.299 made in the same time period. It has the same wheelsets and it has a decoder fitted, so far I have had no bother with it running over Hornby pointwork, although I had to increase the depth of the point flangeways on a couple of new Hornby china made points with a small needle file for it and others to run. As has been rightly said, was the loco a good runner wihtout DCC? A loco should be in good fettle before DCC conversion, Is the pointwork laid level and flat? Link to comment Share on other sites More sharing options...
SamES Posted December 2, 2012 Author Share Posted December 2, 2012 [reply]magfan said: Thanks for the replies. Have looked into replacing wheels. Not straightforward. Service sheet 262B covers three models and a different wheel set is listed for each one! I tested the loco before conversion. It ran well forwards and reverse on straight and curved track. But, I didn't try it over points. Will continue the investigation and report back. Regards Link to comment Share on other sites More sharing options...
SamES Posted December 3, 2012 Author Share Posted December 3, 2012 Hello again. Have had a good look at this today and have found the cause of the problem.I should say causes of the problem. I had solved the problem when I reduced the size of the inside flange on the centre drive wheels. The reason the loco continued to stop was that two of our points are slightly different to the others. And, sods law prevailing, they were the ones I was testing on. The cause of the problem is the front and rear left hand driving wheels, looking from the rear of the loco, shorting the two centre rails when going in the turnout direction. The short occurs when the wheels are just going onto the frog from the curved centre rail or, off the frog and onto the curved centre rail in the other direction. On close inspection, I noticed that on the two points causing the problem, the two centre rails that go almost to a point at the frog, where closer to the frog than on other points that weren't causing a problem. On the problem points the gap is around 2mm. On the others the gap is about 3mm on the curved rial and slightly more on the straight rail. The problem points are an R8072 and an R8073. I bought them second hand. Apart from the already mentioned, they look well used but are otherwise identical to ones I have bought new. As I have said, other locos with narrower tyres and smaller wheels don't have a problem so it's a combination of the wider tyres on this loco and the narrow gaps on the points I am looking into modifying the points. Thanks again for all the help with this. Regards Link to comment Share on other sites More sharing options...
SamES Posted December 4, 2012 Author Share Posted December 4, 2012 Hello again. Have modified the two points causing the problem and R239 loco is passing over them with no problems now. I filed the corners nearest the frog on the two centre rails to increase the gap between them. Thanks again for all the help. Regards Link to comment Share on other sites More sharing options...
The son of Triangman Posted December 4, 2012 Share Posted December 4, 2012 Glad to be able to help. I thought the flange depth and clearance on the point work would come into it somewhere. In recent years the Hornby points have gained a decreased flangeway clearance depth and the application of a file usually does the job. Link to comment Share on other sites More sharing options...
SamES Posted December 5, 2012 Author Share Posted December 5, 2012 [reply]magfan said: Hello magfan. Thanks for your reply. You say you have converted a lot of older locos so I am hoping you can help with another DCC question. All the locos I have converted so far have had a component or components wired accross the motor. No problem on modern Hornby locos as i have followed conversion instructions on this site. On older locos there is also a component wired accross motor but it looks different. Is it an older version of the same component or does it need replacing with a new type for DCC working? Regards Link to comment Share on other sites More sharing options...
Gregd99 Posted December 5, 2012 Share Posted December 5, 2012 SamES, best to open this as another thread for a complete topic change . Do have a search through the forum as there has been a fair bit of discussions on old loco conversions. Link to comment Share on other sites More sharing options...
The son of Triangman Posted December 6, 2012 Share Posted December 6, 2012 I tend to keep the capacitor unless it's causing problems as they occassionally do. It's left mainly for legal reasons and the law surrounding TV and radio interferance. As has been said the decoders have radio suppression on the boards so it's belt and braces to leave the capacitor. It's been a source of debate for yonks in the model railway fraternity as to remove or keep. Link to comment Share on other sites More sharing options...
The son of Triangman Posted December 6, 2012 Share Posted December 6, 2012 If the capacitor is doing no harm and I mean not causing the decoder to malfunction then I would just leave it in place. Hornby seem to have left them in place in most of their fitting guides as well. Link to comment Share on other sites More sharing options...
The son of Triangman Posted December 6, 2012 Share Posted December 6, 2012 If it's good enough for Hornby then it's good enough for me. Link to comment Share on other sites More sharing options...
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