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Slow-running or quartering problem?


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I have the Hornby R3498 SDJR 3F loco. It runs reasonably well but I think it could be better. When running very slowly, it's not totally smooth, almost a little jerky.  It runs slow, slightly surges ahead, then runs slow.  I suspect it's quartering may be a little off. Does anyone know how to improve that?

 

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OK, I just did some googling and it seems the best way is to remove the loco's driving wheels and make adjustments. This sounds like a bit to much surgery for me, for what is really a minor problem. I was hoping there might be a quick tweak I could try that might improve it.

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It could be a number of things but if it has traction tyres and the wheels are held in by a plastic keeper plate it is unlikely to be quartering, Traction tyres not fitting snugly in their grooves are a common problem, but so are dirty wheels as the Railroad loco is so light, Stuffing the side tanks with lead improves pick up but at the end of the day these are kids toys and slow running is not their forte, add in a bit of wear and  they aren't great at creeping along. They do seem to like PWM controllers or even half wave for slow running. What controller do you use?

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This appears to be one of the unfortunate models fitted with Hornby's SSPP (Super Strong Pulling Power :wacko: ) chassis. This is not one of the better engineered products on the market (see below).

 

http://www.hornbyguide.com/service_sheet_details.asp?sheetid=73

 

It is unlikely to be quartering and probably misaligned traction tyres or the sprung rear axle* out of alignment. The spring tension is quite critical. I am assuming the wheels and pickups are clean and functional of course.

 

The quartering is easy to check. Remove the motor and then try to rotate the wheels by hand. It must be possible to drive all six wheels turning any one of them without tight spots. Check that none of the coupling rods are bent. If this is OK (probable - Hornby wheels are jig aligned and their quartering can be relied upon, always provided they haven't been tampered with) then it's down to the tyres (make sure they are clean and correctly fitted in their groove - at worst remove them and try without - take care not to loose the coupling rod screws!) or the springs (good luck! - see the service sheet).

 

* Spring suspension is the best way to ensure good track holding and pick up. However it is tricky to set up correctly and where only one axle is sprung it should be the centre axle. Springing one of the outer axles is asking for trouble. However, as long as the tension is correct, the chassis is capable of good results. I have one that runs really well.

 

 

Failure to run slowly is down to the controller. I have yet to find anything my H & M Powermaster can't tame - even Hornby 0-4-0Ts.

 

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I agree that the quartering being out is unlikely on a Hornby model; their wheels are fixed very solidly to the axles and quartered correctly in the factory, very unlikely to go off quarter unless seriously abused.

 

I think this may be the same chassis as used on my 2721, 2761; it was also used on the J83 and trainset 08s as well.  The rear axle is sprung with two springs bearing directly down on it, no bearing plate.  I got mine to run fairly smoothly after a lot of faff, and got so used to dismantling and re-assembling the loco that I reckon I could do it under fire in the dark in a foxhole quicker than Martin Sheen could do the same to his M-15 in Apocalypse Now.  

 

Key points to look out for are the pickups, the cleanliness of the axle grooves, how tight the keeper plate screws are, absolute cleanliness between the keeper plate and the bottom of the chassis, and the aforementioned springs.  On my loco, they were too strong and lifted the bunker visibly, affecting the balance of the loco and contact between railhead and wheels, not to mention bothering the pickups.  The answer as suggested in the owners manual sheet (you can download this free from Hornby as a PDF if you don't have one) is too cut the springs down if they are too powerful or stretch them if they are not powerful enough, which seems a little crude and brutal.  I trimmed mine and ballasted the bunker until I'd got the back end to sit down without bottoming out the springs, and smoothed the now sharply cut ends of the springs with emery cloth.  They had previously been rough enough to scratch grooves in the axle, so I swapped the front and rear wheelsets,

 

I also binned the traction tyres.  I hate these things, they never sit properly in their groove and while on this model they are on the centre wheelset and cannot affect pickup which is to the leading and trailing wheels only, if they stand proud of their groove, the chassis rocks about the axis of the centre axle and loses pick up at one end or the other, and if they don't stand proud of their groove they don't have any effect.  I don't need the haulage anyway on my small BLT, so off they came to be given the opportunity of an exciting new career in the landfill industry.  The loco runs perfectly well without them if the track is well laid, and I have since replaced them on 2761 with a wheelset from a scrapped 08 I was given and didn't really want, and have fitted an extra pickup to this wheelset.

 

As has been said, you can find out if it's a mechanically induced problem by removing the motor and carefully pushing the rolling chassis along, feeling for tight spots.  If there is a tight spot which comes gradually and goes gradually, then it is possibly a wheel face rubbing on the rear of the coupling rod, and if it only happens with the body on means that something is fouling the body somewhere.  Clean it thoroughly, reassemble carefully, work on the rear sprung axle and the ballasting until you are happy with it, wash out the old lube and relube parsimoniously in all the spots on the owner's manual (I use a syringe with a hypo needle for this).  Use a lump of BluTac or similar to hold small screws so they don't get lost.  

 

Controllers do make a difference, especially DC ones; I use a Gaugemaster.  Slow running is asking a lot of a volume produced RTR toy and by and large our locos do very well, considering that we want them to run as slowly and smoothly as possible at the exact time that current is low and mechanical resistance is at it's highest, as is drag from the train.  DCC has stayalives to solve much of this, and the voltage is constantly 12vdc, but DC has to do the best it can.  A bit of TLC of the sort we have outlined can make a big difference.

 

Never used Bullfrog Snot, but I've heard good things about it.  It certainly won't be worse than the traction tyres, Satan's expectorant.

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I had similar problems with the Hornby J94 which is sprung on the centre axle. I found that bending the spring to put more downward pressure on the axle  helped but ultimately I’ll bin the Hornby mech and replace it. The 3F IIRC also has a fair bit of slop in the rods unless they’ve upgraded the chassis which does not help especially at low speed. Comet does a replacement chassis for the 3F if you feel adventurous?

 

Cheers

 

David

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On 06/09/2020 at 14:39, The Johnster said:

Controllers do make a difference, especially DC ones; I use a Gaugemaster.  Slow running is asking a lot of a volume produced RTR toy and by and large our locos do very well, considering that we want them to run as slowly and smoothly as possible at the exact time that current is low and mechanical resistance is at it's highest, as is drag from the train.  DCC has stayalives to solve much of this, and the voltage is constantly 12vdc, but DC has to do the best it can.  A bit of TLC of the sort we have outlined can make a big difference.

Thanks for your feedback. In what ways, though, are Railroad models actually toys? Sure, they're more basic (less detail) but my SDJR 3F does look like an actual 3F and runs reasonably well. If it were really a toy, would it not be out of proportion, have major scale problems, and only vaguely resemble the real thing? My understanding was that the Railroad  items were still scale models, just more basic and less detailed. Not being sarcastic or anything, just a friendly question. :-)

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3 minutes ago, GreenDiesel said:

Thanks for your feedback. In what ways, though, are Railroad models actually toys? Sure, they're more basic (less detail) but my SDJR 3F does look like an actual 3F and runs reasonably well. If it were really a toy, would it not be out of proportion, have major scale problems, and only vaguely resemble the real thing? My understanding was that the Railroad  items were still scale models, just more basic and less detailed. Not being sarcastic or anything, just a friendly question. :-)

I don’t think I said that Railroad models were toys, in fact I do not mention Railroad at all, though this chassis is used on locos that have been in the Railroad range.  But I think it is fair to regard these as volume produced toys in that they have their origins in Triang Hornby locos that were never ‘scale models’ and were intended mostly to be used by children with train sets.  The axle spacing is wrong for a Jinty as well as everything else it is used for and derives from the original Rovex Jinty of 1955, designed to use the same coupling rods as the Black Princess.  The boilers have unrealistic plastic skirts to hide the motor and gears, which I regard as a toy-like feature.  
 

If you compare the near-scale Bachmann Jinty with the Hornby, you will be able to see what I mean; the Baccy is a very superior model, and has a very superior price to go with it!

 

I have a Railroad mk1 BG which is a very satisfactory model, but items in the range that are based on older mechanisms like the generic Jinty chassis based 0-6-0s are badly compromised.  I ‘live with’ the fundamental errors on my 2721, and would not describe it as a scale model of anything. The wrong axle spacing means that the splashers are in the wrong place, and nothing much can be done about the boiler skirts, which are at least less prominent on this than the Jinty or J86, being overshadowed by the panniers.  The original chimney was tapered the wrong way to release the body from the mould, and the safety valve cover looked like an upturned brass plated flower pot; these have been replaced on my loco with the correct parallel chimney and a cast safety valve cover with a representation of safety valves in it. 
 

There are other work-ups; new buffers, smokebox dart, real coal, cab window glazing, lamp irons, repaint, a crew, cab floorboards, but the truth is it’ll always be a sow’s ear that I can’t make a silk purse out of, and, sadly, I’d have to regard your S&DJ 3F in the same light, though the livery is splendid snd well enough applied. 
 

This is not to say that such locos cannot give us great amounts of pleasure and satisfaction, but I bought the 2721 very cheap as a non-running fixer-upper fun project; I would never have bought such a compromised lo-fi model otherwise.  I wouldn’t have bought this if I’d known the faff I’d have to endure to get a decent performance out of her, but she’s now a useful member of the stud.  

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4 hours ago, GreenDiesel said:

Thanks for your feedback. In what ways, though, are Railroad models actually toys? Sure, they're more basic (less detail) but my SDJR 3F does look like an actual 3F and runs reasonably well. If it were really a toy, would it not be out of proportion, have major scale problems, and only vaguely resemble the real thing? My understanding was that the Railroad  items were still scale models, just more basic and less detailed...

There's no universal description to cover Railroad, other than it is the product that Hornby brands this way, largely based on older tooling.

 

The particular example you have is slightly off scale - the wheelbase has dimensions fixed in the 1950s, as a reasonable compromise to enable it to power a wide range of models, while being true scale for none - but looks well enough to pass. There's far worse in Railroad, the basic 0-4-0 used under Smokey Joe and the rest of his family a good example, and somewhat better, such as the Railroad A4.

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8 hours ago, The Johnster said:

I don’t think I said that Railroad models were toys, in fact I do not mention Railroad at all, though this chassis is used on locos that have been in the Railroad range.  But I think it is fair to regard these as volume produced toys in that they have their origins in Triang Hornby locos that were never ‘scale models’ and were intended mostly to be used by children with train sets.  The axle spacing is wrong for a Jinty as well as everything else it is used for and derives from the original Rovex Jinty of 1955, designed to use the same coupling rods as the Black Princess.  The boilers have unrealistic plastic skirts to hide the motor and gears, which I regard as a toy-like feature.  
 

If you compare the near-scale Bachmann Jinty with the Hornby, you will be able to see what I mean; the Baccy is a very superior model, and has a very superior price to go with it!

 

I have a Railroad mk1 BG which is a very satisfactory model, but items in the range that are based on older mechanisms like the generic Jinty chassis based 0-6-0s are badly compromised.  I ‘live with’ the fundamental errors on my 2721, and would not describe it as a scale model of anything. The wrong axle spacing means that the splashers are in the wrong place, and nothing much can be done about the boiler skirts, which are at least less prominent on this than the Jinty or J86, being overshadowed by the panniers.  The original chimney was tapered the wrong way to release the body from the mould, and the safety valve cover looked like an upturned brass plated flower pot; these have been replaced on my loco with the correct parallel chimney and a cast safety valve cover with a representation of safety valves in it. 
 

There are other work-ups; new buffers, smokebox dart, real coal, cab window glazing, lamp irons, repaint, a crew, cab floorboards, but the truth is it’ll always be a sow’s ear that I can’t make a silk purse out of, and, sadly, I’d have to regard your S&DJ 3F in the same light, though the livery is splendid snd well enough applied. 
 

This is not to say that such locos cannot give us great amounts of pleasure and satisfaction, but I bought the 2721 very cheap as a non-running fixer-upper fun project; I would never have bought such a compromised lo-fi model otherwise.  I wouldn’t have bought this if I’d known the faff I’d have to endure to get a decent performance out of her, but she’s now a useful member of the stud.  

Thx! I see what you mean. I’ve often been tempted to get the Baccy version and may consider that. 

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This is well worth a try.

 

https://www.youtube.com/watch?v=gU4FOlPqMu4

 

I have tried it with one of mine and it works, but mine hauls light loads, (about 10 vans). Under stall conditions (don't ask!), the gears did disengage, but under normal conditions, it is fine. 

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8 hours ago, Tiptonian said:

This is well worth a try.

 

https://www.youtube.com/watch?v=gU4FOlPqMu4

 

I have tried it with one of mine and it works, but mine hauls light loads, (about 10 vans). Under stall conditions (don't ask!), the gears did disengage, but under normal conditions, it is fine. 

I just tried this and it definitely made an improvement. Thanks for suggesting this! It runs better forwards than in reverse.

 

In reverse, it doesn't stall, but it's not consistent and smooth. It moves slowly then kind of lunges and then moves slowly again. This is what it was doing before but less extreme.  At any rate, it's an improvement. I'll keep tinkering. 

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Interesting video. I would have left the driven axle alone and allowed vertical play in the other two.

Doesn't she appear to have an eccentric wheel or something causing 'bobbing'? Ot is just me screen/eyes?

 

I would assume this is the earlier R.052 etc. chassis with drive on the front axle. Rigidity is not a feature of the SSPP chassis.

I trying to find the earlier video referred to.

 

EDIT

It can't be - reference is made to centre axle drive. I should have listened properly the first time.

Edited by Il Grifone
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