Hornby Thompson L1

[7013]

Having read what Simon Kohler has written On MREmag I humbly withdraw any concerns/complaints I had over the L1. I would buy one without any hesitation when my particular modelling era appears.

[micklner]

Having read the comments from Simon Kohler in MRE he appears to be asking how many people have had problems with the front pony truck derailing. My one doesnt have this problem.

It is still however derailing the rear bogie . Back to back was tight and has been moved out to the correct width. It only does it in reverse when the set nearest the drivers lifts on curves and jumps off the rail. I have cured 99% of the problem by adding a small spring and a washer to the bogie locating post (this was also loose and I have glued the post tight.). The bogie is now staying on the tracks but I now am getting slight wheelspin on some points of the tracks which are not perfectly flat. This will be cured by removing small pieces of spring until the chassis is laying correctly on the rails.

Overall the Loco is superb and recomended.:D

 

EDIT

 

Washer has now been filed thinner which has allowed more flex in the spring . Loco now is now 100% no slipping etc.

[wilks]

On my Hornby L1 I have fitted a small soft spring to the front pony truck to stop it from derailing. In tests carried out sofar the fiiting of the spring keeps the pony truck straight and has stopped derailments. Note I had previously tried tightening the retaining srcews and adding a small lead weight to no avail.

 

The spring is 6mm diameter by 11mm long. I bought mine from my local model railway shop, the lady said it was from a Hornby Castle bogie spring.

 

The spring fits between the inside faces of the pony truck. To hold the spring in place super glued a piece of plasticard (approx 1mm thick) between the sides. The bottom of the spring is then wound over the front edge of the piece of plasticard. The spring grips the plasticard, with most of it approx 7mm above the plasticard.

 

To centralise the pony truck a small piece (1mm thick) of plasticard is glued on the underside of the footplate behind the front buffer beam, leaving a small gap behind the beam. The top of the spring locates over the piece of plasticard.

 

This is very simple fix, requires no cutting or drilling of the body or pony truck. It is fairly unobtrusive, it may interfere with the scale coupling hook but it appears to work by applying downward pressure and centralising the pony truck.

 

Wilks

[robmcg]

Thankyou Wilks,

 

That is an excellent suggestion and I like the practical effect, I'll try it on my green BR version which has an occasional front wheel derailment, on the transition from type 3 radius to straight, after perhaps seeing if a tweak to widen the back-to-back doesn't improve it, as well as checking assembly of the pony truck etc.

 

Rob

[Garry D100]

Just noticed on Modelfair that the Late Crest L1 DCC fitted is out

[stewartingram]

I haven't got my L1 yet, still waiting for 67722 to be released. I did however observe at length the Hornby one running round their Warley layout. It was noticeable that the front truck turned with the curves, but upon coming out onto the straights, it retained its posture at an angle for some time. And no, this wasn't a trick of the light, I moved around to sight it from different angles, and on different curves. In defence though, it did NOT derail. As my LMS tank is of a similar design but has only run basically up and down a plank, I've refrained from any mods as yet, although it is a poor performer on the curves of points, consistently derailing. I've refrained from posting till now, as I felt (1) not having 1st hand experience of an L1 & (2) speculative comments are detrimental to the both the discussion and the manufacturer. However I think my comments on the Warley observation are justified, and I am not particularly worried even if my (eventual) L1 also has the symptoms, as it looks easy enough to fix. Gut feeling, looking at the LMS tank and previous posts, is that the 2-pin pivot does not allow the bogie to re-centralise (correct word?) as it comes out of the curve. Any slight track irregularity at this point with a non-centralised bogie may possibly cause derailment; if trackwork is good it will probably be ok. This perhaps explains the lack of complaints to Hornby. Again a reasoned guess, stiffness on the pivots along with lack of downward force is probably the cause? I do feel that the single pivot point is mechanically a better design here.

[Theakerr]

A friend brought over his L1 last night and there is one set of points where the front truck continuously de-railed. None of my other locos de-rail here including the K3, WD 2-8-0 and the 2-10-0 which also have a single wheel front truck. Back to back was slightly out. Corrected it - no improvement. Put in a little lead - no improvement. The point (switch) where it derails is somewhat unique. It is a code 100 LR st right hand turnout and it is approached by a curve that matches the point turnout curve radius. The front truck just wants to keep following the curve. Did a bit of an analysis and it seems to me that if the track is level there is no way the truck can come off due to how it is held in place on the loco. However if there is the slightest hint of a gradient up to the switch rails then the loco could ride up on the driving wheels creating a bit of an inverted V and the truck will continue on its merry way. Will be doing some checking in the next couple of days to see if my track is not level. However, this set of points did pass my crude track laying test. Specifically, take a nine coach train and run the entire thing in reverse at about 1/2 speed and see if anything de-rails. Also when going backwards the rear truck de-railed at a Code 75 crossing. Beautiful runner though. Pulled 9 of my old heavy lima Mk 1's with no problem. Started and stopped so smoothly. Finally, see my post re reed switch activation. I use a lot of reed switches and this makes it a show stopper.

[CUTLER2579]

Its in at Hattons 67722 as R2914X.

 

Hello

 

This is an automatically generated email to tell you that Hornby Model Railways R2914X Thompson L1 Class 2-6-4T 67722 in BR black with late crest livery- Shed plate is provisionally '31a Cambridge' (DCC Fitted) is now in stock and ready to purchase at http://www.ehattons.com/StockDetail.aspx?SID=32119 for £86.00.

 

Its Good News Week.

[Dan Hamblin]

It is a code 100 LR st right hand turnout and it is approached by a curve that matches the point turnout curve radius. The front truck just wants to keep following the curve. Did a bit of an analysis and it seems to me that if the track is level there is no way the truck can come off due to how it is held in place on the loco. However if there is the slightest hint of a gradient up to the switch rails then the loco could ride up on the driving wheels creating a bit of an inverted V and the truck will continue on its merry way.

Exactly the same problem with my 38xx model, only with a left hand turn out and left hand curve leading up to it. The track is level, but the wheelset is skewed over so hard that the flange climbs up the point blade. Both locos share the same bogie design as I understand it.

 

Regards,

 

Dan

[robmcg]

... The point (switch) where it derails is somewhat unique. It is a code 100 LR st right hand turnout and it is approached by a curve that matches the point turnout curve radius. The front truck just wants to keep following the curve. Did a bit of an analysis and it seems to me that if the track is level there is no way the truck can come off due to how it is held in place on the loco. However if there is the slightest hint of a gradient up to the switch rails then the loco could ride up on the driving wheels creating a bit of an inverted V and the truck will continue on its merry way. Will be doing some checking in the next couple of days to .....

 

I had exactly the same de-railment issue with my apple green BR version, the 'straightening up' effect on a code 100 Peco medium radius point, after a short piece of type 2 radius Peco code 100 Setrack, regardless of whether the point was set straight ahead or curved (at the slightly wider radius). This was all pinned to flat thick medium density fibreboard (MDF). Pretty flat, but not absolutely perfect.

 

My black early crest BR version does not derail anywhere. Neither loco has the front model hook style coupling fitted. No weights added, back-to-back flanges look pretty close to correct. Vertical and longitudinal play in the pony truck mounts is the same in both locos.

 

After looking at this thread and others on the subject, I sat down today to compare both locos., in search of an answer for the de-railing green version This has been fitted by me with the supplied 3-link coupling, as well as the longish brake pipe. Both locos have both transit screws back in place snugly, both have similar vertical free play for the pony truck in the captive 2-pin arrangement. In both engines the front wheels adopt a sideways angle somewhat greater than needed, due to the gauge and tolerances of the flanges/wheels. The black one had a very slightly stiffly rotating axle, but this has gone after a little running.

 

The green one had slight roughness in the mounts when the pony truck when pressed up against the body and moved from side-to-side. I rubbed it back and forth to remove any flashing or roughness of surfaces involved. This loco (when right-way-up, sitting on bare flat surface) showed a tendency to twist its axle when the flange pushed on right-hand curves, lifting the outer flange very slightly, possible because of roughness or slight binding in the pivot pins, or binding with the underside of the engine frame/smokebox area, or a remote chance, contact with brake pipe or 3-link coupling. The black one did not show this tendency at all. With the green one, fitted with the coupling and brake pipe, there was almost zero clearance between the coupling and front face of the pony truck. The fore-aft movement of the pony in its mounts was not always smooth, either. (Sorry for being long-winded!)

 

So I wiggled and moved all the various pivots and joints through a full range, using mild pressure, until they seemed to be more 'free'. Especially I ensured that the fore-aft movement of the pony truck was free, regardless of angle of rotation. I tested this also by watching the loco start after stopping in reverse, and vice versa, it shows a few mm of fore-aft by design, after all.

 

Result, no derailments at all, at any speed up to a scale 60mph.

 

Conclusion? I cannot be sure but I think the free play of all the parts is essential, and that a tendency to twist the front axle when some sort of binding occurs in the pony truck mounts is at the nub of it.

 

Hope this is of some value. and this photo shows the issue where the derailment USED to happen.. just about or ahead of the green loco..

 

 

Rob

[Theakerr]

Picture shows what appears to be happening with the LNER version. Will have a look at the truck and see if there are any places where it might be catching. Will post results

[robmcg]

Here is a video showing several passes of my two L1s. Alas I wasn't able to replicate a derailment! It does show the pony truck quite well especially in the last scene.

 

 

Rob

 

Edit; also found this excellent L1 prototype clip,

 

[Theakerr]

Status as promised. There were number of VERY small "burrs" on various components. I cleaned those off but the front bogie still wants to go its merry way. Did some more investigation and I found that my tack is not quiet level. At the critical point I can just feel the loco rocking on the centre axle. I am certain that is the real problem. Unlike many of my loco's there is zero vertical float in the centre wheels so I suspect that even the smallest track imperfection will permit the formation of the inverted V that I hypothesised which in turn allows the front bogie to continue following its established direction. Corrective action would appear to be one of 3 options. 1) correct the track imperfection. Very difficult to do because of its location (under a bridge) and since I dont have any problems with my own locos, I will leave it as is. 2) put in some sort of spring arrangement either as described in this thread or a leaf type spring as per the K3. If my friend wants me to this will probably be the route I go. 3) file a little bit out of the centre wheel housing so that there is a little vertical float. I would be very loath to do this on a new model and especially one that runs so well otherwise. It would be interesting to see if the Black L1's have any float on the centre axle.

[robmcg]

That is very interesting. Neither of my locos (as in the video) have any fore-aft rocking at all. They sit dead square on flat track. The black version has barely detectable vertical foat in the centre axle, under 0.5mm at a guess, and the BR green version no detable float at all. I think the axles are drilled without vertical play, probably to spread adhesive weight.

 

There may be a good case for replacement by Hornby if the engine rocks noticeably fore-aft on a flat surface. The parts are made on drilling jigs which may sometimes wander or err.

 

That said, the vertical, horizontal and rotational tolerances and free play in the front pony and rear bogie should accomodate a small amount of inaccuracy in the set of the driving wheels on track with some rises and falls and twist..

 

The spring seems like another do-able option. I wouldn't personally want to remove the wheels and ream the axle-housing, or 'ease' them, then re-quarter the wheels and re-assemble..a spring would be far easier!

 

MRE online magazine today had a contribution suggesting that accurate back-to-back gauge on the wheels of L1s and other similar locos was a very important factor too.

 

Best,

 

Rob

[Graham_Muz]

To summarise with respect to the front pony truck I would recommend the two following points:

 

1) Ensure that the chassis baseplate screws (the ones that also held the packing brackets in place) have been fully re-tightened after the bracket removal. If this is slightly loose the front pony fixing system will also be loose.

 

2) Check that the back to back of the pony wheel is correct (it is likely to be too narrow). This does appear to be a regular issue with many items from China

 

I hope this helps

[34theletterbetweenB&D]

I took advantage of the pre-Christmas absence on a girlie shopping run of Mrs Santa to access my example (put away until that day when I will receive it ) to give it a test run. No trouble at all, though the most severe test on the layout is a medium radius off a 30" radius curve. There are some bumps where the boards warped after a roof leak, tackled those with no bother. But I don't like the 2mm fore and aft slop of the pony truck, so the single pivot mod it will receive. There's bound to be a digital camera around over Christmas, will post a picture if no one else shows a similar mod and I can master the technology.

[Theakerr]

Should clarify the rocking I reported. The problem is with my track. Using a strait edge the wheels are completely flat with no rocking at all. Also no vertical movement of the centre wheel set. Almost all if not all my other loco's have a bit to a lot of vertical float in the centre wheel set, thus they can accommodate a degree of miss-alignment in the track. Rob, I think you have a very good point about why the L1 is such a good puller when you say that all 6 wheels are in contact with the track. This is good, but it does introduce a new dimension to track laying. I consider my self to be better than average (false modesty in a situation like this does not help solve a problem) and one has to wonder how many people would end up being totally frustrated by this situation. One has to wonder if, with the introduction of near museum quality models, it my soon be necessary to put floating (hornblock) axles on "commercial" locomotives. I know it will add to the price but based on the length of this thread and others there clearly is a problem although one can argue about just how big it is.

[wilks]

Following my post of the 14th December I have taken some photos of the simple modification I have made which works :

 

[robmcg]

Should clarify the rocking I reported. The problem is with my track. Using a strait edge the wheels are completely flat with no rocking at all. Also no vertical movement of the centre wheel set. Almost all if not all my other loco's have a bit to a lot of vertical float in the centre wheel set, thus they can accommodate a degree of miss-alignment in the track. Rob, I think you have a very good point about why the L1 is such a good puller when you say that all 6 wheels are in contact with the track. This is good, but it does introduce a new dimension to track laying. I consider my self to be better than average (false modesty in a situation like this does not help solve a problem) and one has to wonder how many people would end up being totally frustrated by this situation. One has to wonder if, with the introduction of near museum quality models, it my soon be necessary to put floating (hornblock) axles on "commercial" locomotives. I know it will add to the price but based on the length of this thread and others there clearly is a problem although one can argue about just how big it is.

 

Indeed the accuracy of recent models does sometimes give rise to unwanted consequences. It's hard to say how widespread the problem is.

 

Perhaps a spring and/or weight arrangement like Wilks' would be practical, (thankyou Wilks for the photos) .. if you can find and bits and pieces which would suit.

Otherwise, as you say, some more complex answer may be necessary. At least we have a reasonable idea why the problem occurs... slight variations in clearances of gauge, bearings and pivots, and track alignment (which may not be much different from the prototypes!).

Any spring would be painted matt black and be near invisible, too.

Lovely, lovely models!

 

Rob

[Theakerr]

Many thanks for the pictures. I was going to try to put the spring inside the chassis screw mounting hole. Will discuss with the actual owner and see what he wants to do. We know your solution works. Question though, do you see any sign of the plastic keeper plate flexing in front of the foremost mounting screw. I have looked at my friends model and without to much effort I can make the plastic "come off" the two positioning pins.

[31A]

As an early Christmas present to myself, I toddled along to Monk Bar Models this afternoon and collected my late crest 67722. A splendid model, very well pleased with it!

 

I was interested to see, however, (under a magnifying glass) that the smokebox door carries a 30C (Bishops Stortford) shed plate, rather than the 'provisionally' announced 31A .

 

Not that this particularly bothers me, but I was interested because I'd been discussing this a little while ago with a retired Cambridge engineman friend of mine, who was a fireman in the 1950s and kept good records of the locos he worked on. My trusty 1959 Locoshed book shows 67722 (and a few others) as 31A Cambridge, but my chum couldn't remember them being allocated there. He suspected they may have been Bishops Stortford locos, displaced by the Liverpool St. electrification and possibly were only at Cambridge for a short while.

 

Anyway, that's just a little aside really which might be of interest to some people as I hadn't seen the change of shed plate mentioned elsewhere. Not meant to detract in any way from the delightful model, and I'm currently playing 'spot the difference' between this one and the 'early crest' 67772!

[Bernard Lamb]

As an early Christmas present to myself, I toddled along to Monk Bar Models this afternoon and collected my late crest 67722.

 

I was interested to see, however, (under a magnifying glass) that the smokebox door carries a 30C (Bishops Stortford) shed plate, rather than the 'provisionally' announced 31A .

 

Even better. It was a Bishop's Stortford loco after moving from Stratford. Slips into pedant mode. Note the apostrophe. Thus it could turn up on the bank holiday services to Clacton etc via the Braintree branch.

Well that's my justification. I do prefer the curved front to the fotplate. Sooo much more stylish. Retires before the flack starts flying.

Bernard

[7013]

Thanks for the photos Wilks, a very simple and effective way of stiffening up the front pony truck.

[31A]

I'm currently playing 'spot the difference' between this one and the 'early crest' 67772!

 

Well this is a good game, and I'm still playing it - has anyone who's got both BR versions compared the cab roofs?

 

 

Apologies if the above photo isn't clear enough to show what I mean!

[robmcg]

Well this is a good game, and I'm still playing it - has anyone who's got both BR versions compared the cab roofs?

 

 

Apologies if the above photo isn't clear enough to show what I mean!

 

 

Well, I'll play. Is it the drainage bead? ...or whatever it's called. Curved vs inverted 'v'?

 

Rob