Silver Fox 17 Posted April 13 Share Posted April 13 There has been a few issues with people having difficulty coupling the Mk3 vehicles and having them uncouple, but, many have not had the issue which did make me wonder. However, tonight as I was clearing all of my stock of the boards it was the first time to look underneath, as they had just been left there, and I noticed 1) it is a completely different design to the Mk1, and more importantly 2) some of the drop drop arms for the couplers seem more "flexible". I bought 6 coaches and on two of them I had a "solid" type at one end and a "loose" type at the other. When I say "solid" I mean there is no vertical movement, just like the Mk1, but the "loose" one just seems soft and floppy allowing it to sag/droop. The arms do not seem to be clipped or supported as well as the others. These are the first coaches I have fitted the WHWW magnets too and that made it very noticeable when the magnets on some ends was nearly a full magnet down on the adjacent coach. Obviously when they were allowed close enough the low one jumped up to the correct height. Hopefully someone else may spot this now as well. Link to comment Share on other sites More sharing options...
Silver Fox 17 Posted April 14 Author Share Posted April 14 Here are two coaches in one photo and a coach and power car in the other and you can see the droop differently from one to the adjacent vehicle. Link to comment Share on other sites More sharing options...
Andrew-372848 Posted April 14 Share Posted April 14 I only have two of the coaches, but both are a little droopy on both ends compared to the power/dummy locomotive. As you say the attraction of the magnetic couplings compensates for this very well. I seemed to get into a right tangle with the original couplings compared to some of the other rolling stock I had at the time and have now switched entirely to the WHWW ones. I prefer the simplicity of just pulling the rolling stock apart over the ability to shunt with out manual intervention. Link to comment Share on other sites More sharing options...
Leslie-359394 Posted April 14 Share Posted April 14 I have been looking to replace mine with the WHWW couplers. which of the four different types are you using? Link to comment Share on other sites More sharing options...
Andrew-372848 Posted April 14 Share Posted April 14 I initially got the starter pack and after some experimentation found that the Close coupling is optimal for my layout and that is what I've fitted on these and my other rolling stock. However, you might get away with the Extra Close ones if you don't have tight curves or crossovers. Link to comment Share on other sites More sharing options...
ateshci Posted April 14 Share Posted April 14 Standard TT-couplings depend on a rigid vertical mount to keep them horizontal. Many of the plastic close-couple holders are either distorted or are mounted in enclosures having too much vertical play when they move. Link to comment Share on other sites More sharing options...
Rallymatt Posted April 14 Share Posted April 14 The Tillig style couplings really don’t like out of tolerance height. From what you are saying @Silver Fox 17, it’s the coupling shank into the NEM pocket rather than the Kinetic part drooping, ie the shank is a ‘loose fit’ I cured a similar issue on one of my Arnold Ferry vans with a drop of Rocket Card Glue. It is enough to hold the shank rigid and in alignment but can be overcome and cleaned back to new state if needed. Link to comment Share on other sites More sharing options...
D9020 Nimbus Posted April 14 Share Posted April 14 This is a problem with other NEM coupler mounts too — notably the NEM362 used in OO and HO. Sometimes the fitting of a shim is recommended. It's particularly tricky if Kadees are being used where the height is critical. The NEM 355/358 box used in TT (and N) is particularly complex as it has to allow for lifting couplings like the standard Arnold N type as well as couplings that need a fixed height such as the NEM 359 (the standard TT coupler) and Fleischmann Profi N gauge coupler (used to be used on Roco TT models too). Link to comment Share on other sites More sharing options...
Leslie-359394 Posted April 14 Share Posted April 14 Thank you for the information Andrew-372848. Link to comment Share on other sites More sharing options...
Silver Fox 17 Posted April 14 Author Share Posted April 14 1 hour ago, Rallymatt said: The Tillig style couplings really don’t like out of tolerance height. From what you are saying @Silver Fox 17, it’s the coupling shank into the NEM pocket rather than the Kinetic part drooping, ie the shank is a ‘loose fit’ I cured a similar issue on one of my Arnold Ferry vans with a drop of Rocket Card Glue. It is enough to hold the shank rigid and in alignment but can be overcome and cleaned back to new state if needed. I don't really know which part is looser than others as I have not had one apart yet to check as I have been too busy. Obviously this is where the main problem lays with the out of alignment issues. Link to comment Share on other sites More sharing options...
Silver Fox 17 Posted April 15 Author Share Posted April 15 Here is a comparison between the Mk1/Stanier and Mk3 couplings. I have not removed the Mk3 but dont think it has any connection to the body like the Mk1 does with its locating clip behind the buffer beam. The pivot point is a lot further forward. Link to comment Share on other sites More sharing options...
GMD Posted April 15 Share Posted April 15 @Silver Fox 17 Thanks for this photo - helpful to get a close up of the differences. Link to comment Share on other sites More sharing options...
Moccasin Posted April 15 Share Posted April 15 Out of interest, how do these arrangements compare to OO coaches? Are they scaled down or quite different? Just curious as to how they developed the solutions. Link to comment Share on other sites More sharing options...
Rallymatt Posted April 15 Share Posted April 15 From the photo, I would say the KK arm locates into a slot in the floor on the MK3 as opposed to in the pocket behind the buffer beam on the MK1. Neither should be excessively loose through design. The only thing I can see from photos (earlier side on shots) the coupling shank does seem to be not parallel with the NEM pocket that is part of the KK system. Maybe some tweaking with that can sort the issue Link to comment Share on other sites More sharing options...
Silver Fox 17 Posted April 15 Author Share Posted April 15 (edited) I have dismantled a Mk3 coupling and there is no clip/slot in the floor to prevent droop. The arm is held up by the screwed plate and its thinness, length, and soft material allows it to drop. There is no hole in the floor but a moulded slot which is just for the arm to move out on corners. Edited April 15 by Silver Fox 17 1 Link to comment Share on other sites More sharing options...
Rallymatt Posted April 15 Share Posted April 15 @Silver Fox 17 thanks for the more involved disassembly and photos, the bit I saw is merely a guide. That could answer why the whole assembly could droop 1 Link to comment Share on other sites More sharing options...
BurwellMike Posted April 17 Share Posted April 17 3 Mk3 coaches arrived yesterday and with great excitement I went to install them between the two power cars (which incidentally coupled ok and ran backwards/forwards with no issues on all radii). That's where the fun stopped! Coupling up proved to be nigh on impossible. As others have pointed out the levels of the couplings were different. When I did persuade them to join (by lifting one coach to line up) they derailed when entering bends on radius 3, I assumed because some of the weight was carried through the coupling. Undeterred and having been forewarned by the excellent advice on this forum I fitted magnetic couplings which I had bought in anticipation of this problem. First issue was that the hunt magnetic couplings where loose in a couple of the NEM sockets and tended to pull out under load. Eventually I got them to stay in long enough for testing and success the rake of 3 coaches and 2 power cars successfully ran on all curves (2-4) pulled by the power car. However in reverse (push mode) disaster, the coach bogies refuse to take the third radius. They seem to jump track on leaving the curve rather than entering. The same happens with just two coaches and no dummy power car. All bogies swivel freely, wheels seem to be reasonably free running (but not as free as the Mk1 coaches). I have tried all sized magnetic couplings with the same result. My rake of 5 Mk1 coaches run perfectly on the same track in pull or push directions as do all the small freight wagons. I am now completely stumped. Has anyone else had problems with the magnetic couplings staying in the sockets or problems operating the HST in push mode. All advice gratefully received. Link to comment Share on other sites More sharing options...
Moccasin Posted April 17 Share Posted April 17 Just for balance, my four coaches coupled well last night. There is one that I need to keep an eye on -it suddenly uncoupled and I subsequently found an unconventional HST arrangement going around the oval (coach - dummy - power car - coach-coach-coach) I think this was down to poor/hasty track laying as the decoupling happened twice in the same place and a jolt from a larger than desirable gap could have caused it. 1 Link to comment Share on other sites More sharing options...
Rallymatt Posted April 17 Share Posted April 17 @BurwellMike You mentioned some of the Hunt magnetic couplings were/are loose in the NEM socket. If they have any side to side play in the pocket, it can cause the KK mechanism to push an out of tolerance amount on the bogie and cause the derailment. The other thing is to make sure the polarity on the magnets is correct, so they connect end to end not on the sides of the magnets. If it does, remove one and flip it over, take care with Hunt 3D printed magnetic couplings, they are prone to shatter/snap. 1 Link to comment Share on other sites More sharing options...
Rallymatt Posted April 17 Share Posted April 17 @Silver Fox 17 Is there any scope for adjustment with the retaining plate of the coupling? The KK arm/bracket looks square so maybe an adjustment to the retaining plate that supports it in operation could lift the coupling to correct height. Could be as easy as tightening the retaining plate screws. I’m sure there was an element of adjustment built in to KK systems this way. Link to comment Share on other sites More sharing options...
BurwellMike Posted April 17 Share Posted April 17 @Moccasin out of the four coupling points I got one to join as I expected (and as easily as the rest of my stock). This was by swapping ends to find two with a matching height. I know what you mean about unconventional formations when the couplings give up! Maybe I am just unlucky with my three coaches. The two power coaches couple ok. I don't think it is down to the track laying. My thought is that if the front bogie on my A1's/A4's can all handle my track a Mk 3 HST bogie should take it in its stride - especially on a 3rd radius Link to comment Share on other sites More sharing options...
Mulsanne88 Posted April 17 Share Posted April 17 I am expecting my 4 GWR mk3s today to add to the 1 mk3 already received Am feeling a bit wary given recent coupling comments i am going straight for hunt couplings, my layout does involve ‘reversing’ out of a storage siding around 3rd radius curves so I am a bit nervous Will report later Link to comment Share on other sites More sharing options...
BurwellMike Posted April 17 Share Posted April 17 @Rallymatt Thanks for that. Yes polarity of the magnets are all correct. There is definitely some movement of the couplings in the socket, the Hunt connector does not seem wide enough for a snug fit (or the NEM is too wide?). Maybe I will try an experiment with fitting a couple with a low tack adhesive to keep them central. 1 Link to comment Share on other sites More sharing options...
BurwellMike Posted April 17 Share Posted April 17 @Mulsanne88 I have seen plenty of videos of rakes much longer than mine running at speed with no issues so hopefully I am the exception and yours will be fine! I'll report on progress in sorting mine out Link to comment Share on other sites More sharing options...
Silver Fox 17 Posted April 17 Author Share Posted April 17 1 hour ago, Rallymatt said: @Silver Fox 17 Is there any scope for adjustment with the retaining plate of the coupling? The KK arm/bracket looks square so maybe an adjustment to the retaining plate that supports it in operation could lift the coupling to correct height. Could be as easy as tightening the retaining plate screws. I’m sure there was an element of adjustment built in to KK systems this way. I dont really know Matt. I did not look at any adjustment as I was fitting the Hunt ones. Putting the spring back was a pain and stretched the ends which I had to reshape so dont want to dismantle again. I will say reversing mine around the normal corners one coach will keep derailing. The Mk3 coupling design does not give as good an arc as the Mk1, it is a lot sharper and given the length of the coach I was surprised. My thought is it should have been designed to pivot around the bogie pin just the same as the Mk1. Also, as mentioned by someone these are not as free running as Mk1's but still a lot better than the original tank wagons. 2 Link to comment Share on other sites More sharing options...
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