llamafish Posted June 16, 2010 Share Posted June 16, 2010 Hi all, I have a rake of 6 Bachmann MK1s, and all but one run on Commonwealth bogies, and these five all give me the same problem - They constantly derail, usually on corners and points. Is there a way to prevent these derailments from happening? The rake rarely completes a full circuit of a circa 1.5M test track, in fact, I don't think it ever has. I've tried loosening the screws on a few, to see whether the bogie casing was catching on the body, to no avail. I then tried a bogie swap between 2 coaches in the rake, and still the same problem. Can anyone help with a solution? I'm getting frustrated I'm unable to use the coaches properly. Thanks. Link to post Share on other sites More sharing options...
SRman Posted June 17, 2010 Share Posted June 17, 2010 Check the wheel back-to-back measurements to see if any are out of gauge. I usually do that bogie screw loosening trick myself to allow a little more up and down movement. Finally, try removing the coach weights - I have found that the mark 1s run perfectly well without them and, in fact, allow longer trains to be run. Also, there's less drag on the couplings and bogies at the front of the train with the lighter coaches. Link to post Share on other sites More sharing options...
RMweb Gold Dagworth Posted June 17, 2010 RMweb Gold Share Posted June 17, 2010 The problem is caused by the dampers on the sides of the bogies hitting the underside of the coach. If you unscrew the bogie and trim off the top of the damper level with the top of the bogie frame the bogie will then turn freely. You cannot see this mod from normal viewing angles. Andi Link to post Share on other sites More sharing options...
llamafish Posted June 17, 2010 Author Share Posted June 17, 2010 Thanks guys, I'll try both suggestions. Link to post Share on other sites More sharing options...
Dan Hamblin Posted June 17, 2010 Share Posted June 17, 2010 Not only the top of the dampers, but you also need to make a small cut out for the top of the wheelsets in the existing pocket on the underframe. Regards, Dan Link to post Share on other sites More sharing options...
Portchullin Tatty Posted June 17, 2010 Share Posted June 17, 2010 The problem is caused by the dampers on the sides of the bogies hitting the underside of the coach. If you unscrew the bogie and trim off the top of the damper level with the top of the bogie frame the bogie will then turn freely. You cannot see this mod from normal viewing angles. Andi Andi's suggestion that the main issue with the Commonwealths concurs with my views, but the overtightening of the screw securing the bogie in place is another issue I have had and the whole coach is quite light so I have hidden some lead on the bogies - the combination of these improves things lots. Link to post Share on other sites More sharing options...
llamafish Posted June 17, 2010 Author Share Posted June 17, 2010 Andi's suggestion that the main issue with the Commonwealths concurs with my views, but the overtightening of the screw securing the bogie in place is another issue I have had and the whole coach is quite light so I have hidden some lead on the bogies - the combination of these improves things lots. Thanks. I was also thinking of adding a metal washer underneath each bogie, to separate the bogie from the frame a bit, and possibly find a longer screw to accommodate it. I have 5 to do so I might end up trying a different method on each carriage, but the advice has helped me a lot. Link to post Share on other sites More sharing options...
RMweb Gold Dagworth Posted June 17, 2010 RMweb Gold Share Posted June 17, 2010 Andi's suggestion that the main issue with the Commonwealths concurs with my views, but the overtightening of the screw securing the bogie in place is another issue I have had and the whole coach is quite light so I have hidden some lead on the bogies - the combination of these improves things lots. IIRC I pointed you to my cure at Scaleforum when you were struggling with them on Portchullin. Nice to see it at Showcase by the way.. Andi Link to post Share on other sites More sharing options...
Guest Max Stafford Posted June 17, 2010 Share Posted June 17, 2010 Thanks for the top tip, Dag! Dave. Link to post Share on other sites More sharing options...
RMweb Premium Gwiwer Posted June 18, 2010 RMweb Premium Share Posted June 18, 2010 This isn't a problem I have encountered with Commonwealth bogie stock but I do have a couple of Bachmann Mk1 coaches on leaf spring bogies which exhibit the same problem. I'll give the clearances a check on them. My next question relates to your own curve radius. If nothing else derails there may be no issue with the track at all but what is your minimum curve radius and do your coaches derail on curves, often at the same spot or just at random? Those of mine which derail do so irrespective of train length and formation (and I regularly run trains of up to 14 similar coaches without a problem) but tend to come off at the same spots every time which is where the bogie enters the second part of a reverse-curve or S-bend. It appears that the cause of the derailing is the bogie being asked to swing from one arc to the other across the straight-ahead mid-point. There is no apparent problem with coupler swing which was a potential cause I eliminated early on. The Hornby Pullmans exhibit similar derailing tendencies as does anything coupled to a class 50. The same locations cause the problem but on these vehicles it has been traced to the coupler arm not travelling smoothly across the moulded guide section within the underframe. This is the moulding with two concave cut-out sections designed to aid the coupler in swinging freely across the full arc but they seem to catch on the point. That has been solved on the Pullmans by carving this piece away but this cannot be done easily on the 50 as the underframe is metal. Link to post Share on other sites More sharing options...
llamafish Posted June 18, 2010 Author Share Posted June 18, 2010 I can only run mine on Hornby large radii curves, however, the coaches seem to want to carry straight on, as a result, the leading bogie of the carriage will derail closely followed by the trailing bogie and most of the other coaches. I'm hoping that removing the top of the dampers will solve this, as hopefully they will be able to move more freely. Link to post Share on other sites More sharing options...
Miss Prism Posted June 18, 2010 Share Posted June 18, 2010 Interesting post, Gwiwer. The drawbar force amidst your lengthy trains will be quite high, and I'm wondering whether the friction in the coupler arm travelling across the moulded guide section might be a potential problem. Do you keep this area lubricated? Link to post Share on other sites More sharing options...
Portchullin Tatty Posted June 18, 2010 Share Posted June 18, 2010 IIRC I pointed you to my cure at Scaleforum when you were struggling with them on Portchullin. Nice to see it at Showcase by the way.. Andi Agghh, that was you! Thank you for that! You were spot on, it did improve things a lot! The overtightening of the screw was the other problem but it took me some time to find this. Link to post Share on other sites More sharing options...
RMweb Gold Dagworth Posted June 18, 2010 RMweb Gold Share Posted June 18, 2010 Agghh, that was you! Thank you for that! You were spot on, it did improve things a lot! The overtightening of the screw was the other problem but it took me some time to find this. For the problem of the screws being over tightened I added some little washers to each screw that are small enough to go through the hole in the bogie. Without looking I'd guess they are M2 washers. These mean that the screws can be done up tight but still allow the bogie enough slop to move freely. Also it may be worthy of note that all my Bachmann coaches have had the close coupling mech removed and the couplings replaced with body mounted Kadees. Andi Link to post Share on other sites More sharing options...
llamafish Posted June 18, 2010 Author Share Posted June 18, 2010 That was something I was thinking of doing, as I mentioned a few posts back, looks like I will be definitely be trying to find some if someone else says it works! Link to post Share on other sites More sharing options...
llamafish Posted June 18, 2010 Author Share Posted June 18, 2010 I must thank Dagworth for the excellent advice, I still had one or two derailments, but far less than before, and they even managed to complete a full circuit of the same test track. However, I had a new problem with a brand new Heljan 27, yet I was running it on exactly the same Hornby track, controller, adaptor etc as previously, but this time it would run smoothly for a while, before completely cutting out, and I can't get it moving again until I move it or switch the controller off and on again, and it isn't at the same point either, yet I had no problems when testing it Thursday night? I hope this isn't a sign that my loco is on the blink already? Link to post Share on other sites More sharing options...
John Urquhart Posted December 3, 2016 Share Posted December 3, 2016 The problem is caused by the dampers on the sides of the bogies hitting the underside of the coach. If you unscrew the bogie and trim off the top of the damper level with the top of the bogie frame the bogie will then turn freely. You cannot see this mod from normal viewing angles. Andi How I wish I had come across this post before I embarked on my project of replacing all my Commonwealth bogies with Mk1s... such a simple modification has cured the derailment problem across my entire fleet! Big thank you Dagworth Link to post Share on other sites More sharing options...
34theletterbetweenB&D Posted December 3, 2016 Share Posted December 3, 2016 ... I had a new problem with a brand new Heljan 27, yet I was running it on exactly the same Hornby track, controller, adaptor etc as previously, but this time it would run smoothly for a while, before completely cutting out, and I can't get it moving again until I move it or switch the controller off and on again, and it isn't at the same point either, yet I had no problems when testing it Thursday night? I hope this isn't a sign that my loco is on the blink already? And did Llamafish work out that his Heljan 27 was fine, but that the controller didn't have sufficient current supply to continuously operate it? Link to post Share on other sites More sharing options...
John Tomlinson Posted December 3, 2016 Share Posted December 3, 2016 I would concur with Dagworth in #14 above. The close coupling mechanism, by which I mean the plastic oval and spring that sits between bogie and chassis and the lug for the spring on the chassis, was identified as a cause of derailment when the coaches were first produced. This is particularly so at points of change in gradient, the mechanism fouls the bogie and prevents it turning properly on curves. I proved this once myself in spectacular fashion with a 9F on nine coaches - the test wasn't repeated! I have also adopted the solution of body mounted Kadees, set to give clearance for my minimum curves, approx 27 inches radius. Using this arrangement I can with confidence push a rake uphill, round curves and through facing pointwork, without derailment. My coaches also have the weights removed, IIRC if you put them on scales this reduces the total per vehicle from around 160g to 130g, still a perfectly acceptable load per axle. John. Link to post Share on other sites More sharing options...
johnashp Posted November 18, 2017 Share Posted November 18, 2017 I just stumbled upon this thread and how glad I am that I did! I treated myself to 3 Bachmann coaches for my birthday:- A nearly new (looks virtually unused) Bachmann-BR-Mk1-Maroon-Restaurant-Car-Coach-No-W1915-39-103. And two new coaches which had been extracted by the seller from a set, I think: "Bachmann OO 30-285 coaches PAIR OF Mk1 BR MAROON COACHES" How disappointed I was at the constant derailing at points and on curves. I checked the back to back and they were OK on the new two but, on the restaurant car, they were a tad tight so I had a go at pushing them apart slightly. No change! I am a terrible modeller so wondered about replacing the bogies. If so, which ones should I get and would it work? Also, if there are weights, where would they be located? Hope this one can be solved as I don't want to waste my investment in these! Thanks!! Link to post Share on other sites More sharing options...
RMweb Gold Phil Bullock Posted November 18, 2017 RMweb Gold Share Posted November 18, 2017 I just stumbled upon this thread and how glad I am that I did! I treated myself to 3 Bachmann coaches for my birthday:- A nearly new (looks virtually unused) Bachmann-BR-Mk1-Maroon-Restaurant-Car-Coach-No-W1915-39-103. And two new coaches which had been extracted by the seller from a set, I think: "Bachmann OO 30-285 coaches PAIR OF Mk1 BR MAROON COACHES" How disappointed I was at the constant derailing at points and on curves. I checked the back to back and they were OK on the new two but, on the restaurant car, they were a tad tight so I had a go at pushing them apart slightly. No change! I am a terrible modeller so wondered about replacing the bogies. If so, which ones should I get and would it work? Also, if there are weights, where would they be located? Hope this one can be solved as I don't want to waste my investment in these! Thanks!! First job - have you loosened the bogie retaining screws a bit? They are usually too tight to allow sufficient tramp Come back if that doesn't solve the problem Phil Link to post Share on other sites More sharing options...
RMweb Premium Gwiwer Posted November 18, 2017 RMweb Premium Share Posted November 18, 2017 Definitely back off the bogie retaining screws by about a quarter-turn. Then another quarter-turn if the problem hasn’t gone away. If it still derails after that we can suggest other things Link to post Share on other sites More sharing options...
johnashp Posted November 18, 2017 Share Posted November 18, 2017 First job - have you loosened the bogie retaining screws a bit? They are usually too tight to allow sufficient tramp Come back if that doesn't solve the problem Phil Thanks Phil. I did loosen a couple off when I was trying to determine what was happening. Will go back in tomorrow and check them all and report back. My first reaction to finding this thread was "at least I'm not alone". I was pretty disappointed at my first running of these coaches! Link to post Share on other sites More sharing options...
RMweb Gold Phil Bullock Posted November 18, 2017 RMweb Gold Share Posted November 18, 2017 Yes it is frustrating but usually find these problems with Bachmann MK1 coaches - but they are so good as to be worthwhile sorting the issues out 1st step - back to backs, you have already been there 2nd step - bogie screws 3rd step check nothing on bogie is fouling underframe, common culprit on commonwealths is the top of the shock absorbers on the bogie side frames are just too tall, taking a mil off them cures that issue P Link to post Share on other sites More sharing options...
RMweb Premium Gwiwer Posted November 18, 2017 RMweb Premium Share Posted November 18, 2017 Phil comments on the Commonwealth bogie examples. Perhaps by random chance I have had more difficulty with the leaf-spring bogie examples. It does seem to be random though as with over 100 Bachmann Mk1s perhaps 20 have caused problems. Another thing which can work, though I have no idea as to why, is to reverse the direction of the coach within the rake or to alter the formation of the train on a trial and error basis to see what works. In a rake of 10 NSE coaches there are a couple of TSOs which are only happy running one way and one of those (which now only has a coupler at one end) really doesn’t like having any load coupled behind it. The same train formed of b/g stock seldom gives any problems but the same formation again using maroon stock more of which have leaf-spring bogies required some juggling to get a happy set-up. Again I have no idea why these oddities exist. All these coaches weigh the same. But couple a BG at the front, which has no interior detal and is therefore lighter, and it will drag off on the first bend due to the rolling resistance of the heavier stock behind. And don’t get me started on keeping a rake of GUVs on the rails. Having said that much they are generally very good coaches and worth the price even now. Link to post Share on other sites More sharing options...
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