Didn't see that one coming!!!

[The Johnster]

Having had a few issues with my brand new (when I bought it 4 years ago) 42xx shedding bits (rear coupling on the first test run, buffers, crankpins, keeper plate retaining screw) I am now in the habit of checking everything on new or 2h locos as they come into my posession by giving things a gentle tug to ensure that they are securely fixed in.  But my new (bought last December) 5101 has caught me out with a new one that I had not predicted!

 

I checked the buffers, crankpins, all the screws, when the loco arrived and it has been fine up until this week when a stiffness appeared at a specific point in the driving wheel revolution.  Now, in my defence, I model the South Wales Valleys where the normal method of working was to have the loco running smokebox first up the valley and bunker first down, so I have perhaps not been observing the right hand side of the loco as closesly as the left because that is the way Cwmdimbath is orientated.  Can't be anything serious, I thought, and investigated, finding nothing immediately visibly wrong, 

 

It was not until I ran the loco the 'wrong way round', so that the right hand side was presented to the viewer, that I realised that the rear face of the cylinders, which holds the slide bars and the motion bracket, was not in any way attached to the rest of the cylinder block and was flapping about in the fresh air as the loco moved, to the detriment of smooth control.  I now have the loco dismantled and discovered that the corresponding lh part is also being held in place by no more than an interference fit and willpower.  I reckon the solution is to superglue the pieces back into their correct locations, and perhaps to lubricate the piston rod a little or even bore out the hole very slightly to minimise movement that might cause a repeat of the phenomenal phenonenum, but I'm a bit miffed.

 

More poor design and ineffective quality control from Hornby, IMHO an indicator of a producer under pressure and cutting corners at a time when their image and reputation is their biggest friend in a world that is not being economically kind to them.  I reckon I am capable of sorting the matter out myself and do not want the faff of sending the loco back under warranty, though I will do that if I have to, but this would not be a solution available to those who are out of warranty and whose comfort zone/skillset does not encompass work of this sort.  Of the 3 Hornby locos I've bought brand new over the last 4 years, 2 have suffered in this way, a 66% failure rate.  My W4 Peckett dropped it's rear coupling once but I'll overlook that.  Over 5 years I've bought 2 brand new and several secondhand Bachmann locos, which have all run perfectly and nothing has dropped off of any of them, a 100% success rate.rh

 

Oh, and the rh connecting rod crankpin, the same one that fell of my 42xx, was loose as well, now remedied of course but I will clearly have to check it periodically.  Come on Hornby, you can (and should) do better than this, especially as a competitor 5101 is about to hit the market!

[GWR-fan]

Alas, these are long term issues with Hornby steam locomotives.  I check the crankpin for tightness on every Hornby steam outline loco when purchased,  as I learned long ago that when a new loco starts to limp along then it is time to go looking for a crankpin on the trackside.   The slide bars are another issue where it seems the bars are retained by magic to the cylinder rear face.  The bars just push in with seemingly no friction required.  A drop of superglue does give some confidence that the part will stay in position.

 

I am not saying that Bachmann are superior quality however I have not experienced these issues with this brand.  Bachmann have their own quirks like the tiny rivets retaining the valve gear breaking resulting in some delicate surgery using brass trackpins and solder. 

[atom3624]

Not forgetting issues which can be created through poor handling / thin coupling rods / fragile valve gear.

This is obviously avoidable.

I have found some rivets / pins are a touch too loose, permitting too much lateral movement at times.

 

Al.

[The Johnster]

I would add that my 5101 has, in it's 10 months of service so far, been very lightly used hauling 2 or 3 coach trains on a flat BLT at low speeds over short distances over Peco medium radius turnouts, a task that should be well within it's capablitlies.  I'm fussy about driving and smooth starts and stops; it's had a pretty easy life!*  It does get handled fairly often, as there is not enough room in the fy to keep all the stock on the track all the time, much as I would like this to be the case, but I am careful in my handling. 

 

Chinese manufacturers and assembly plants, even the cheapest ones, are capable of very high quality work, but you get the level of QC that you pay for, and it does look as if H are cutting corners in this respect.  I keep wishlisting for a decent 2721 pannier to current standards, but I would prefer Bachmann or Dapol to make it in preference to Hornby... 

 

Dapol has it's QC problems as well, but they are well known and rectifiable; by and large, replacing the wheelsets and the NEM coupling mountings will result in a trouble free future.  Some of the older toolings, those with Wrenn or Hornby Dublo DNA, are what they are and to be fair priced accordingly, as are Hornby's Railroad offerings, but this is a matter of detailing rather than running issues and important moving bits behaving like Britannias on the S & C.  A piston rod coming out of it's hole and digging into the ballast on the forward stroke can cause a good bit of damage to a loco, and to any stock, but especially kit stock, that it then drops from a height on to the top of, especially if you run at speed.

 

*Tondu's 5101s were employed on exactly such work, and though they had some impressive bank to cope with, were hardly ever close to the limit of what they could do.  The daily Porthcawl-Cardiff 5 coach 'residential' might have got them warmed up a bit, but much of their valley work was pretty easy and they worked turn and about with 57xx panniers on this.

[The Johnster]

The plot thickens.

 

Replacing the rear covers proved straightforward enough, but they both refused to sit flush to the cylinder casing and stood proud about a 10th of a mm.  Ok, I thought, I wouldn't put up with it in a new loco but I'll live with it; it's not obvious unless you look for it.  Ah, the innocence of youth...

 

Careful re-assembly, and a test run.  Loco runs very slowly and motor gets hot; immediate halt to proceedings.  Check everything, seems ok, remove keeper plate to find that one of the bearings that hold the axles in the cradle formed by the axle channel in the chassis block has come out of place, front left.  Problem solved; carefully re-assemble, test run, loco runs very slowly and motor gets hot; immediated halt to proceedings, problem not solved at all.  Hornby 1, Johnster 0.

 

OK, we're into fault finding process of elimination territory now.  First move, remove motor so that I can push the loco by hand and feel for the tight spot if there is one as there seems to be.  But you can't remove the motor!  Seriously; it sits in a cradle and the end covers for the bearings can be removed, in which case you can waggle it about, but because of the flywheel on the shaft and the separate housing for the worm gear, which cannot be removed as far as I can see, and the apparent lack of movement in the worm when the motor and flywheel are waggled means that there must be some sort of universal/cv joint flexible drive shaft hidden behind the gear housing, a thing for which there seems no need on this model.  Hornby 2, Johnster 0

 

Steady on, now, Johnster, don't worry about it, forget about removing the motor for now and let's attack the beast underneath to further the fault finding.   Carefully remove keeper plate, wheels, and connecting rod/xhead/piston rod assembly.  Nothing wrong under there, replace wheels and keeper plate, and test run without connecting rod fitted.  Loco runs very slowly and motor gets hot; a halt is called to proceedings.  I'm starting to scratch my head a bit now, which is never a good idea because the sawdust gets everywhere.  Hornby 3, Johnster 0.

 

Perhaps it's a problem in the DCC-ready chip; ok, let's remove that and hardwire the feed wires from the pickup plungers to the motor temporarily.  Test run; loco runs very slowly and motor gets very hot, so a halt is called to proceedings.  Hornby 4, Johnster 0.  Next move, take the keeper plate and the wheels off again and test run the motor.  Runs perfectly, Hornby 4, Johnster 1, now we've established that the fault is to do with the wheels or motion and not the motor, circuitry, or drive train.

 

Go away and have a cup of tea, come back for a fresh look.  Try reassembly with great care double checking at each stage, and have a look, closely, at everything relating to wheels and motion.

 

Aha!!!

 

Who'd have thunk it, look at that! 

 

The leading wheel flange is fouling on the rear face of the cylinders which are now standing proud of the casing by about a tenth of a mm, and the tread face is fouling too, both sides.  There doens't need to be much clearance, but there does clearly need to be some clearance, and it must be maintained across the entire range of sideplay for the leading wheelset; there is also no sideplay available as the fouling point is the same both sides.  I haven't put the wheels in the wrong way; you physically can't because the cog gear is offset to one side and the joint for the rear coupling rod is behind the big end crankpin; the wheels will simply not go in any other way because the of the offset cog and the different axle spacings.  Therefore, I have not got that wrong.  The problem is the result of the tenth mm that the rear cylinder face now stands proud, and the location of the cylinder block is determined by a relief that accepts it in the front of the chassis block, so it will only go in one position and I can't get that wrong either!

 

The original clearance between the front wheel and the rear face of the cylinders must have been prettiy minimal before; I must remember to check out how this is done on real 5101s next time I see one.  There is of course need for more sideplay for the front axle on the model than the real loco, and the fact that the wheels are 4 and a quarter inches further out from the centre line of the loco than a scale equivalent and that the real wheels are probably another inch thinner scale equivalant no doubt helps!   

 

Hornby 0, Johnster 1, all Hornby goals dissallowed because it's their fault that the rear cylinder faces came out and and refused to go back correctly.  I am going to have to remove material from the rear face of the cylinders to clear the front driving wheels.  If I were doing the job again, I would ream out the inside of the cylinder block to accept the cylinder rear face piece, but its too late for that now; I mention it as potentially useful guidance for anyone else whose Hornby 5101 suffers the same fate!

 

Another cup of tea and an hour watching telly with the squeeze before I put it all back together and test run; if it still doesn't run properly Iain D will hear the scream in Australia, but I'm pretty confident at the moment...

[The Johnster]

4144 is now back up and running, and performing as smoothly as she ever did.  I am keeping an eye on the leading lh crankpin, though, as this has undone itself twice during the re-assembly/trial running process, and may have been part of the cause of the original problem.  I have nutspun it down as tight as it will go but I don't trust it!  As for why one out of 6 crankpins should be a problem while all the others stay where they are told to is as much your guess as mine...

[Michael Hodgson]

On 12/09/2021 at 15:20, The Johnster said:

A piston rod coming out of it's hole and digging into the ballast on the forward stroke can cause a good bit of damage to a loco, and to any stock, but especially kit stock, that it then drops from a height on to the top of, especially if you run at speed.

Well, you can't say that isn't prototypical!

 

But at least it didn't happen all that often in 12":1 ft scale.  And when  it did, the cause tended to be missing, incorrect or defective cotter pins and the like, so small bits falling off was an issue for the big railway too.

[The Johnster]

Occasionally, yes, notably involving Firth of Forth on the S & C.  There was a derailment that was the result of the battery box cover on a Western coming open at Ealing Broadway as well.

[adb968008]

And ‘Calamity’ Tangmere at Winchfield in the last decade… November 2013

 

https://assets.publishing.service.gov.uk/media/547c8fa6e5274a428d000139/R132014_140616_Winchfield.pdf

 

Quote

As the train approached Winchfield, about one mile before reaching the station, the fireman saw sparks coming from the right-hand side of the locomotive,
and informed the driver. The driver braked the train gently with the intention of reaching the station. Very soon afterwards there was a bang and a flash as the connecting rod made contact with the conductor rail, and the driver stopped the train immediately. The locomotive came to rest near milepost 391⁄4 at 18:50 hrs. Evidence from the site indicates that, just before it stopped, the connecting rod dropped off the conductor rail and ran along the ground.

 

one of several events that occurred with this loco.

Edited September 18, 2021 by adb968008

[Legend]

16 hours ago, The Johnster said:

4144 is now back up and running, and performing as smoothly as she ever did.  I am keeping an eye on the leading lh crankpin, though, as this has undone itself twice during the re-assembly/trial running process, and may have been part of the cause of the original problem.  I have nutspun it down as tight as it will go but I don't trust it!  As for why one out of 6 crankpins should be a problem while all the others stay where they are told to is as much your guess as mine...

Did you see this months Steam World has an interesting article on Rhondda valley , particularly around Treherbert

[The Johnster]

Tx for the heads up, Legend, will certainly check it out!  

[mike morley]

With kit-built chassis, a crankpin that keeps on undoing itself is regarded as a symptom rather than the cause of the problem.  Less-than-perfect quartering is the usual cause in such situations.  I can't remember the last time I looked at an RTR chassis so I've no idea if it's even possible for the quartering to slip but I would certainly suggest you investigate that possibility very closely.

[The Johnster]

I will do, Mike.  Hornby wheelsets generally hold their quartering pretty well, and the loco is now running smoothly, which suggests that there is no issue at the moment, but I’ll check and continue to keep a close eye on things.  Ran the loco during last night’s running session with no problem, though; having nutspun the crankpin in tight it seems to be staying put so far  

Edited September 18, 2021 by The Johnster

[The Johnster]

Things seem to have settled down with the errant crankpin, touch wood, but it will be a long time before I completely trust the loco again, and I will continue to keep eyes on.