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Discussion Starter · #1 · (Edited)
I have just bought an N gauge Dapol A4, at £130 incl P&P.
As regards detail I can't fault it, it's beautiful, but..... Its traction leaves much to be desired, slipping pretty easily with only 6 coaches on, but worse, far worse, it derails at the drop of a hat. I'm sure my layout's track is far from perfect, but my diesels go round with hardly any derailing, and my steam aren't that much worse, even my Grafar Black 5 only derails relatively rarely these days (or more likely the track has improved ! ).
Is it common for Dapol A4s to be bad derailers (especially the front bogie) ?
Or is it just the one I have bought (which looks pretty much brand new BTW) ?
Is there anything I can do about it ?
Since a few of the worst problem areas are in the middle of curved points (and they're almost new points as well !), how can I do anything much about that ? And doesn't that indicate it isn't the bad quality of my track ?
 

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Discussion Starter · #3 ·
Oh dear..... The loco also seems to be "tightening up" after literally half an hours moderate to light use. Even full DC only produces slow movement which soon stops altogether and the tender motor appears to be getting warm and possibly even smelling a little.
The instructions say it is "pre lubricated" for 30 hours use but then needs oiling. Could this be the problem (after only half an hour ! ) ?
As a frustrating aside, if lubrication is so essential one would have thought they'd provide a small bottle of oil with the loco. Particularly as the cheapest I can find their oil is £6, plus carriage one would have thought.....
 

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...Is it common for Dapol A4s to be bad derailers (especially the front bogie) ?
Or is it just the one I have bought (which looks pretty much brand new BTW) ?
Is there anything I can do about it ?...
Return to retailer, unfit for purpose, for refund is my best suggestion. There's a 'Catch 22' in your situation: you wouldn't be posting this if you have a good idea of N model loco construction, and the confidence to sort out the trouble(s). So best to exercise your rights as a customer, because it doesn't work even on your newest track pieces.
 

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I assume this is an N gauge loco as I find no reference to an OO loco. So my similar problems most recently came from an OO Hornby A2/2, so I looked at the bogie wheels and find these to be slightly wider flanges than others (such as the new W1 which are much better) and somewhat more shallow, I substituted wheels from Wrenn wagons as these are notoriously pizza cutters, wide tyre and deep flange and hey presto perfect running, a wide tyre sometimes finds it is too wide for the point gap especially on tightening curved points when taking the inner track and the thin flange can then jump the track. The Wrenn wheels looked wrong so I found some from another earlier Hornby model and they looked right.
Now when it comes to N I do have OO9 models and the problem you describe also applied to my Heljan locos, same idea flanges both too wide and too shallow so try to swap the bogie wheels out and the problem will probably go away.
 

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Discussion Starter · #7 · (Edited)
I assume this is an N gauge loco as I find no reference to an OO loco. So my similar problems most recently came from an OO Hornby A2/2, so I looked at the bogie wheels and find these to be slightly wider flanges than others (such as the new W1 which are much better) and somewhat more shallow, I substituted wheels from Wrenn wagons as these are notoriously pizza cutters, wide tyre and deep flange and hey presto perfect running, a wide tyre sometimes finds it is too wide for the point gap especially on tightening curved points when taking the inner track and the thin flange can then jump the track. The Wrenn wheels looked wrong so I found some from another earlier Hornby model and they looked right.
Now when it comes to N I do have OO9 models and the problem you describe also applied to my Heljan locos, same idea flanges both too wide and too shallow so try to swap the bogie wheels out and the problem will probably go away.
It is an N gauge and I have edited the thread title to clarify that.
The seller of the loco, which had to go back for repair anyway as there appears to be something wrong with the motor, says the derailing bogie problem is a "known issue", Something about a plastic part needing bending or something as "they warp over time, but it can be fixed".
 

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In other words "not my problem gov" a regular loco using regular track should not do this - period however some manufacturers are not as good as others and it seems never test anything, anyway replacement wheels are cheap but its up to you.
 

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Discussion Starter · #9 ·
The seller has taken advice from a modeller's group and they advised :

" They don't like less than R2 so that's 10.75 inches, 9 inch radius set track points are an absolute "no-no".
Another thing to try is to back the screw that fixes the pony-truck to the loco off say half a turn, sometimes it is too tight out of the box."


I will experiment with backing off the bogie screw when I get a chance but I do not understand why my other steam locos go round them fine though, even at speed.
Further, if there really are a significant number of locos which will not go round those points (due to the radius) you would have thought that a respected manufacturer like Peco would put a warning on them ! I rang Peco and they said the curved points (ST-44 and ST-45) were radius 2 for the inner curve (the outer is radius 3). Peco also suggested I check the gauge of the bogie wheels, 7.315 to 7.366. I will have to do that when I get a chance too, but, to what point should that be those measurements be taken as the flange is diagonal ? Would it be to the top of the flange ?

Last thought, comparing the Farish Black 5 and and Hall (both of which go round all the points no problem at any speed) to the Dapol A4, their bogies are metal whereas the Dapol's is basic, i.e. lighter. I wondered if the extra weight meant more down force and possibly more inertia = less likely to be easily flicked off ?

I do hope I can sort this, partly because that lock cost me £130 (incl P&P) and partly because it is a beautiful model and I would love to keep it. Though that is pointless if it won't go round my track !
 

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...if there really are a significant number of locos which will not go round those points (due to the radius) you would have thought that a respected manufacturer like Peco would put a warning on them !...
The set track radii are 'standardised': and the expectation is that the model manufacturer - in this case Dapol - advises whether their product can negotiate whatever is accepted as the minimum set track radius in that scale, and if not what the minimum radius requirement might be.

As your 4-6-0 types have no trouble, it would be worth testing the A4 with the rear truck wheelset removed, making the model a more compact 4-6-0 than either of the two 4-6-0s you have (if they are all true scale for wheelbase). The loco to tender link may need to be looked at too, to ensure the large rear overhang doesn't bind on the tender front. (The same problem exists in OO, and the brands making pacifics fit flangeless rear truck wheels to avoid this, and space the tenders off very generously.)

Your idea of metal wheelsets is a good one. Without exception metal is always superior to plastic for flanged wheelsets. (A light spring is a good plan on carrying wheels too, but rather trickier in N for my ageing fingers.)
 

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Discussion Starter · #11 ·
The set track radii are 'standardised': and the expectation is that the model manufacturer - in this case Dapol - advises whether their product can negotiate whatever is accepted as the minimum set track radius in that scale, and if not what the minimum radius requirement might be.

As your 4-6-0 types have no trouble, it would be worth testing the A4 with the rear truck wheelset removed, making the model a more compact 4-6-0 than either of the two 4-6-0s you have (if they are all true scale for wheelbase). The loco to tender link may need to be looked at too, to ensure the large rear overhang doesn't bind on the tender front. (The same problem exists in OO, and the brands making pacifics fit flangeless rear truck wheels to avoid this, and space the tenders off very generously.)

Your idea of metal wheelsets is a good one. Without exception metal is always superior to plastic for flanged wheelsets. (A light spring is a good plan on carrying wheels too, but rather trickier in N for my ageing fingers.)
I do not remember seeing anything (in the instructions that came with my Dapol A4) "this model should not be used on layouts with turns smaller than radius 2, particularly on the points". I shall recheck when I get a chance, but, the curved points are radius 2 of the (tighter) inner anyway, so they should go round them !
 

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Discussion Starter · #12 ·
An interesting point from the seller :

I think because of their weight and the fact that the earlier Farish & Minitrix loco's have what is nicknamed 'Pizza' wheels (Larger rims) they can handle code 80 and tighter radius's much better than the later China models. Personally although my test track is made using code 80, the madness behind that decision is because it is more extreme than say code 55 and normally will reveal any problems that a loco may have when I test them.

A similar idea to kristopher1805's above.
 

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Discussion Starter · #13 ·
I assume this is an N gauge loco as I find no reference to an OO loco. So my similar problems most recently came from an OO Hornby A2/2, so I looked at the bogie wheels and find these to be slightly wider flanges than others (such as the new W1 which are much better) and somewhat more shallow, I substituted wheels from Wrenn wagons as these are notoriously pizza cutters, wide tyre and deep flange and hey presto perfect running, a wide tyre sometimes finds it is too wide for the point gap especially on tightening curved points when taking the inner track and the thin flange can then jump the track. The Wrenn wheels looked wrong so I found some from another earlier Hornby model and they looked right.
Now when it comes to N I do have OO9 models and the problem you describe also applied to my Heljan locos, same idea flanges both too wide and too shallow so try to swap the bogie wheels out and the problem will probably go away.
I have been experimenting with swapping the bogie wheels for sets with larger flanges and it has made a big difference, particularly after fine tuning the gauge.
But, as an additional problem, I think there is something wrong with the plastic mount that the bogie fits over (it is obviously under when on the track !). When holding the loco in the air the bogie drops right down, and when putting the loco on the track it is easy for the aforementioned plastic spacer's "front slot" to miss the peg on the chassis which it is supposed to locate over. Under that condition it is permanently displaced to the side whilst running and may well be contributing to the derailing. This is all the more awkward because one cannot easily see if it is correctly in its slot once on the track as the bogie wheels obscure it.
 

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I have just bought an N gauge Dapol A4, at £130 incl P&P. As regards detail I can't fault it, it's beautiful, but..... Its traction leaves much to be desired, slipping pretty easily with only 6 coaches on, but worse, far worse, it derails at the drop of a hat. I'm sure my layout's track is far from perfect, but my diesels go round with hardly any derailing, and my steam aren't that much worse, even my Grafar Black 5 only derails relatively rarely these days (or more likely the track has improved ! ). Is it common for Dapol A4s to be bad derailers (especially the front bogie) ? Or is it just the one I have bought (which looks pretty much brand new BTW) ? Is there anything I can do about it ? Since a few of the worst problem areas are in the middle of curved points (and they're almost new points as well !), how can I do anything much about that ? And doesn't that indicate it isn't the bad quality of my track ?
Did you solve this problem? I had a Dapol Britannia (similar mechanism, I think) which ran really badly. I tried to fix it but without success. Mine was a " bargain" which I bought from Dapol at a show. I should have returned it and asked for my money back but that's s not going to happen if you've taken it apart...
 

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Did you solve this problem? I had a Dapol Britannia (similar mechanism, I think) which ran really badly. I tried to fix it but without success. Mine was a " bargain" which I bought from Dapol at a show. I should have returned it and asked for my money back but that's s not going to happen if you've taken it apart...
The OP :
...is it just the one I have bought (which looks pretty much brand new BTW) ?...
The text in bold suggests to me it should have been a 'return to vendor' rather than return to Dapol.

This is a standing problem with s/h purchases, there's no manufacturer warranty, and quite right too: if the original owner did not or could not return it via the original retailer, or to the manufacturer or their agent if it was a direct purchase, then the matter is out of their hands, who knows what has been done to the item?

The 'dangling bogie' described suggests a broken or missing component, but without specific knowledge of the design I am clueless as to a fix.
 

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Discussion Starter · #16 ·
The OP :

The text in bold suggests to me it should have been a 'return to vendor' rather than return to Dapol.

This is a standing problem with s/h purchases, there's no manufacturer warranty, and quite right too: if the original owner did not or could not return it via the original retailer, or to the manufacturer or their agent if it was a direct purchase, then the matter is out of their hands, who knows what has been done to the item?

The 'dangling bogie' described suggests a broken or missing component, but without specific knowledge of the design I am clueless as to a fix.
I have just bought a new bogie off Dapol (from their spares agents DCC) and it is different from the one originally installed. The plastic mouting is shorter and therefore does not have the cut out to fit into the peg on the chassis. I only had a chance to test it Friday night so will get onto them on Monday about if the wrong one has been sent or the design has been updated
I don't actually think it's much better than the old bogie.
To be fair the E Bay seller, on being told I'd bought anew front bogie for it said he could have sent me one and offered to refund the £10 it cost me (£8 + £2 P&P)

At present I am experimenting with adjustment of the back to back distance on the front bogie wheels, 7.5mm I believe ?
The "pizza cutter" wheels (i.e. larger flanges) off an old coal hopper seem to work better as regards derailing than the originals.
One thing I did note was the front coupler appeared to be catching the chassis at the top so removing it seemed to help. It rarely gets used and the looks better without it so it was not a big problem.
 

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Discussion Starter · #17 ·
Did you solve this problem? I had a Dapol Britannia (similar mechanism, I think) which ran really badly. I tried to fix it but without success. Mine was a " bargain" which I bought from Dapol at a show. I should have returned it and asked for my money back but that's s not going to happen if you've taken it apart...
See above for latest......
Basically I have to keep reminding myself my track cannot be that bad by running my old Grafar Hall round at high speed and that hardly ever derails ! And neither does almost all of my diesel fleet ! !
 

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My experience with stripping down the Brit was there seemed to be quite a lot of slop on the bearings (and perhaps also the drive) and when I put it on a rolling road the loco was thrashing about, which would be most pronounced at the front of the loco. It is quite an unusual design with the motor in the tender driving the wheels on the loco through a cardan shaft. Some German manufacturers also use this design but they seem to work to tighter tolerances. I have fixed other N gauge locos with success, so it was rather annoying to not succeed with this one.
 

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Discussion Starter · #19 ·
My experience with stripping down the Brit was there seemed to be quite a lot of slop on the bearings (and perhaps also the drive) and when I put it on a rolling road the loco was thrashing about, which would be most pronounced at the front of the loco. It is quite an unusual design with the motor in the tender driving the wheels on the loco through a cardan shaft. Some German manufacturers also use this design but they seem to work to tighter tolerances. I have fixed other N gauge locos with success, so it was rather annoying to not succeed with this one.
I love the detail on the Dapol A4, it's a beautiful model, I can see why some people might just buy it to put on display.
But it is not that robust, the constant derailing and handling (swapping about the bogie wheels but also just having to put it back on the track) etc has meant it has already lost one of its front buffers, which, BTW, appear to be moulded as part of the whole locomotive and made of plastic, so I do not see how it is easily repairable, there will be no replacing it from another scrap loco......
My other steam locos are Farish and seem to be metal and much stronger. The downside is significantly less detailing, but, TBH, I would rather have a more robust and better running loco which may not look quite as good up close. After all, from any sort of distance one cannot see much difference anyway !
 

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Hello there. My friend is crazy about train modeling He sends me over an odd site with model railroad buildings and such, but mostly in HO scale. It is difficult to find much, which is good that he is invested in this 3D printer and Tinkercad, which is fantastic. He said that there are lots of videos on YouTube on how to create your own model. Sadly I have no idea how to do it. I have to ask him each time I need something.
 
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