Hornby Steam Locos issues

[Colemand]

I have purchase in my opinion a top model from TMC of Hornby's K1 with Deluxe weathering, dcc fitted etc. Along with a P2 2-8-2 loco from another retailer.

The issue I have with both locos is their front bogies just do not stay on the rails. The K1's bogie will even jump the track mid way round a curve nowhere near a point, joint or other obstacle that could cause a derailment.

In taking a closer look at the loco navigating a curve it appear that the inside wheel lifts and the wheel stops rotating.

I cannot believe that there are not more of us out there with the same issue? especially as I have two locos with the single axle front bogie and a 100% failure rate.

Can anybody suggest anything to help here? I take it being as the K1 has been weathered and DCC fitted then they will was their hands stating that the terms of the warranty has been broken.

 

Thanks for your support.

[johnb]

Need a bit more info, what track and what radius is being used?

 

Also is the track laid absolutely level, is it just one curve or all of them?

 

John

[34theletterbetweenB&D]

The first and essential question is what radius of curve is the derailment occurring on?

 

The good description you give of what happens, the inside wheel lifting and rotation ceasing, is typically the result of a wheel fouling fixed structure, because the curvature is of smaller radius than the model is specified for,

 

Both these models require a minimum 'second radius' (438mm) in the standard UK OO set track systems. Smaller radius set track was in the past available in this system, the 'first radius' at 371mm, but this was abandoned many years ago when the move to closer to scale models was made. (There are also HO track systems offering their own range of curve radii, the same problem is likely to arise if using track from any such system with a radius less than 438mm.)

 

Second factor to look at, if you are sure the curves are second radius or greater, is how closely the tender is coupled. On both locos the tender should be set at the greatest separation the link permits. (The K1 definitely has long and short settings, don't know about the P2.)

 

Hope that helps. There's more yet if these two fail to deliver for you.

[The Johnster]

Does sound like a combination of sharp curvature and track than is not absolutely level especially at the joins is the root of the problem; bigger locos like bigger radius curves to run, and this is a feature of real railways as well.  But also check that the joins are smooth, i.e. that the radius is maintained accurately through the join without a lateral kink.  This is more difficult to achieve than you might think, unless you have laid the track carefully to a drawn out curved pencil line and ensured that it has not wandered off during the fixing procedure.

 

Another thing you might want to look at if you have used track fixing pins is the slight tendency for the track to dip and pull inwards out of gauge if you have been a bit enthusiastic driving the pins home.  The pin head should be driven as far as the top surface of the plastic sleeper, but no further or a) your track will start to distort and/or b) it will attempt to spring back to shape, loosening the pin and losing the accuracy of the fixing.   Any of these factors or a combination of them will provoke the sort of derailing you describe.

 

A good steel or hard plastic straight edge will help you check for level at the railhead.  To check for smooth alignment through the curves, place a spare piece of curved track of the same radius over the join and check that the fixed track beneath lines up.  If you don't have a spare piece of track, make a curved piece of card in the same shape, with pencil marks or notches at the ends representing the position of the rails, but be careful to position it correctly or you will get a 'false reading' in the form of a sort of curved chord from your intended imaginary circle, if that makes sense...

 

Of course, reducing your speed around the curve may help; if you are running at close to the loco's design limit for that curve, then just as on a real railway a speed limit will be needed.  If you want to run fast around curves, then your best solution is to ease the curve; model railway curves are extremely sharp in terms of scale.  But this may not be possible due to lack of room, the perpetual bugbear of railway modelling.

 

If none of this works, you may need to look at the locos, but that is another post...

Edited March 6, 2018 by The Johnster

[Colemand]

Thanks for the replies.

 

I am using peco code 100 with 2nd and 3rd radius curves. The locos derail on both circuits and at any point of the layout. I am concous that the track is not 100% level. However I only experience derailing with these two locos. I woul expect RTR models to negotiate 2nd and 3rd radius curves. There also doesn't seem to be one point of the layout causing problem it seems to be totally random.

The question of speed the K1 will derail at any point even at low speeds.

[Right Away]

As on the "big" railway, certain locomotives having one leading axle have had tendencies to be "track sensitive" to the extent that derailments occured whilst running on poorly laid or poorly maintained permanent way.

 

Short of relaying the suspect trackwork (probably the best solution) you may first wish to consider the following:

 

Do you have or have access to, any other locos with a leading truck which you can test run on your railway and see if these negotiate your track without issue?

Do the models concerned have any form of spring control which applies downward pressure to the leading axle? If so then maybe a slight adjustment may be possible to increase the force on the axle.

[HLT 0109]

Is the pony truck in each case fixed in the same manner as on Hornby's L1 - ie a sloppy sort of arrangement that allows the axle to move forward and backwards as it pivots?  When the L1 first came out it suffered a problem very like OP describes and the cure is to find some method of controlling the fore/aft movement.  As I am unfamiliar with either the K1 or P2 models I can't suggest a remedy for them but perhaps this might be checked as a possible cause.  In the case of my L1, the pony truck would stay turned (and canted) after negotiating a curve or point and then ride over the inside rail.

 

I hope this is some help.

Harold.

[richard.h]

Just to confirm the previous post Locos with a single leading axle do tend to derail more than other types initially but once they are set up correctly the the should perform equally well on level track, I have had models in the past where a tweak of the tension spring(if fitted) or adding a little extra weight solved the problem.

I have a P2 which performed  perfectly well straight out of the box on code 75 track so normally they shouldn't need adjustment.

In your case after checking that the leading pony trucks are moving freely and that the wheels and structure are not binding anywhere I would then run the locos as slowly as possible over the track to try and analyse exactly what is happening, also if you have any spare clean track run the locos on that to see if it track condition that is causing the problem.

[31A]

Is the pony truck in each case fixed in the same manner as on Hornby's L1 - ie a sloppy sort of arrangement that allows the axle to move forward and backwards as it pivots?  When the L1 first came out it suffered a problem very like OP describes and the cure is to find some method of controlling the fore/aft movement.  As I am unfamiliar with either the K1 or P2 models I can't suggest a remedy for them but perhaps this might be checked as a possible cause.  In the case of my L1, the pony truck would stay turned (and canted) after negotiating a curve or point and then ride over the inside rail.

 

I hope this is some help.

Harold.

 

 

The K1 has a more conventional pony truck pivot than the L1, with a single central pivot pin in the same way as a full sized loco.  I can't remember what the P2 is like (mine's boxed up at the moment).

 

If the K1's front steps (supplied as optional detailing parts) have been fitted, it's possible that the pony truck wheels conflict with these on curves causing them to derail.  On some locos where this is a problem, I've solved it by trimming a bit off the leading edge of the steps so that they fit slightly further forward and avoid the pony truck wheels.

[DCB]

Cleaning the inside edges, the gauge corner, of the track is worth doing, not just rubbing ba track rubber flat across the top.   Most modellers seem to watch their locos run up and down a length of track before consigning it to the display cabinet and almost everything new from Hornby and Bachmann seems to need work before they run properly. 

Checking the back to back of the pony truck wheels is a good start, you can use a digital caliper, or as I do make up a template, mine is 14.25mm and 14.5mm, if the 14.25 fits and the 14.5 doesn't its good.  Too wide back to back is a frequent cause of derailing on curves, too narrow a cause of derailing on points.  I also find some pony trucks have far too much side play on the axles which lets the wheels adopt too sharp an angle, turning in too much on curves..  A washer or two on the axle usually fixes this.  Weighting the pony truck with lead often helps as can weakening the spring but this robs adhesion weight if overdone

 

Edit I have found the guard irons which come down in front of the wheels are too long and rub on the rals causing random derailments.

Two Hornby 28XX locos needed them trimmed back amd I think the 42XX and 72XX also needed this mod.

Edited March 7, 2018 by DavidCBroad

[BR60103]

I have a similar problem with my Clan Pacific. At one end the lugs that hold the axle have spread (they're plastic) and prevent the axle from rotating.  Check that you don't have a similar deformity.

[daftbovine]

One of the first things I check is wheel back to back measurements, they are often 'out' even on brand new models.

[eastglosmog]

Had the same problem with my Hornby 28xx 2-8-0.  Curve 572mm radius, so in 4th radius category.  Only happened when running round a left hand curve. The pony truck seemed to stick to the left and not straighten out on reaching the straight bit before the points, with consequence it derailed on the points when set for straight running.   I checked the back to back and it was a bit under (as Daftbovine says, they sometimes are).  Having fixed that, it now runs OK, although it sometimes dithers a bit, so I might try adding a bit more weight to the pony truck or a centering spring.

Edit:  My track is far from perfect, but no other locos fall off it anywhere.  My Bachmann 45xx 2-6-2t goes round that curve and over the points with no trouble at all, whichever way it is running.

Edited March 7, 2018 by eastglosmog

[Colemand]

Thanks all for your advice. I managed to to get root cause and the wheels fouled the front foot steps. A quick push in has given enough clearance to negotiate 2nd radius curves. Time to enjoy this loco.

[The Johnster]

One of the first things I check is wheel back to back measurements, they are often 'out' even on brand new models.

 

I'd say they are often out especially on brand new models; not sure why but assume the manufacturing process is to blame.