Re: Tim V's workbench - latest shenanigans

[Tim V]

Back to my attempts at replicating shunting. Not the sort that you can see at any exhibition, the real thing didn't shunt like that. Getting it all right!

I have never seen shunting authentically replicated in a model environment. For those below a certain age, the kind I'm on about can be seen at about 2:20 on this Youtube video
http://www.youtube.com/watch?v=ASWEpKJ3 ... re=related

This is loose shunting. It can be done in DCC. Onboard uncouplers, I'm using S&W couplings - an etch came my way - it's the Mk1 version. The delayed action is not needed as the uncoupling is in the wagon.

The High Level FlyShunter chassis.

IMG_2409.JPG

An uncoupling relay in place. Jim Smith-Wright has put me onto some smaller relays.

IMG_2410.JPG

The arrangement.

IMG_2411.JPG

[Paul Townsend]

I'm using S&W couplings

Looks good on paper.
Did you consider the Nigel Cliffe DCC A-J uncoupler as some have successfully mounted on locos?
It is so small that it would work in a near empty wagon only needing to hide the drive mech.

Nice as the HL mech doubtless is, Ted Scannel's work on tiny axle hung motor drives etc would be smaller still so you could flyshunt a truly empty wagon?
Might look a bit cluttered around the brakes though so some cunning plan is needed to disguise that.

[Tim V]

I did consider that AJ, however, my experiments led me to conclude that 100% reliability could not be achieved. Remember that the operator could be 10' away from the shunting area. As for Ted Scannell's work - well.....

Some of the other members of the area group have a number of small industrial locos. I have barely seen these locos travel more than 6'. Some of the trains on Clutton travel 1/4 of a real mile, or 1260', whereas other trains might travel a mere 420' in a weekend's show. I am minded of the article by Roy Jackson way back in MRJ18 where he explained his rationale for his building methods. It was reading that again that encouraged me to keep some statistics of the mileages some of my stock travels. There isn't room on Clutton for fiendishly complicated small motors, they would just fail - probably in an embarrassing situation. Again there isn't room for overcomplicated sprung stock - it just fails or has such high maintenance demands that it just ain't worth it.

[rule55]

Very interesting. Getting it all right certainly should encompass miniaturising real railway operation and, as you quite rightly state it hasn't been done anywhere near properly yet. This video demonstrates rather well what we should be attempting to replicate.

I suppose the only thing that troubles me slightly with this approach is that by powering wagons we will be getting further away from the way the real railway operated (a shame as DCC has made it much easier to do just that) and we also limit the way we can marshal and shunt our trains. The problem is that the laws of physics, even in P4, don't seem to scale exactly and so this may well be the only viable approach. In my mind (for what it's worth!) the same issue doesn't arise with auto-uncoupling - it really isn't possible to get a 4mm to the foot shunter to run alongside with a pole.

I wish you well with this Tim, it's something we have needed to tackle for quite sometime and, as a railwayman, it's the one reason why I've never been able to stick around even the best railway exhibition for more than a few hours in the past - the models are fantastic but the way they operate is not always totally convincing.

Tony

[Alan Turner]

The problem is that the laws of physics, even in P4, don't seem to scale exactly and so this may well be the only viable approach.

You're only scaling linear dimensions. time and gravity remain as the full scale world - so no the laws of physics don't scale because the two aspects that define dynamics are not scaled.

Alan

[Paul Townsend]

Perhaps the dcc approach is too controllable and predictable?

How about a heavy wagon with a geared flywheel on board. This might be easier/cheaper to engineer and would introduce a prototypical uncertainty about where it would end up. If the shunter had to run after it he sometimes lost it!

If that is too risky for some, use the flywheel to power it and dcc to apply brakes before demolishing the buffer stop.

This is not to knock Tim's efforts just throwing up ideas, after all he has tried something, but I haven't!

[Noel]

Paul, My memory of school physics is now very feeble, but I wonder what would happen to such a flywheel equipped wagon whilst running in a train? Would it not be just as reluctant to start as it would be to stop? Also, given its reluctance to stop would it not lead to an increase in SPADs? Mind you, it would make driving mineral trains up to signals at danger very interesting...

Noel

[grovenor-2685]

NWSL made a boxcar with such a flywheel for this very purpose, I did once try to fit it in a brake van but I didn't find it satisfactory, maybe it needed more perseverance. But then its not in the current catalogue so maybe it didn't work to well for them either. The parts must be in one of my bits boxes.
regards
Keith

[Paul Townsend]

Paul, My memory of school physics is now very feeble, but I wonder what would happen to such a flywheel equipped wagon whilst running in a train? Would it not be just as reluctant to start as it would be to stop? Also, given its reluctance to stop would it not lead to an increase in SPADs? Mind you, it would make driving mineral trains up to signals at danger very interesting...

Noel

It would certainly affect its train but not hugely so if it were say one of 20 wagons. I doubt if it would make it hard to drive, just different.
Tim's version with a motor/gearbox will also have some effect on the train driving characteristics. Doubtless we will see a BAG demo soon.

In both cases I expect the behaviour of a loose coupled flywheel or motor equipped wagon in the middle of a rake is going to show some strange behaviour of the wagon coupling/buffers, not the equipped wagon if it is S&W but adjacent 3link or AJ rigged wagons will be affected.

[Paul Townsend]

NWSL made a boxcar with such a flywheel for this very purpose, I did once try to fit it in a brake van but I didn't find it satisfactory, maybe it needed more perseverance. But then its not in the current catalogue so maybe it didn't work to well for them either. The parts must be in one of my bits boxes.
regards
Keith

Can you remeber what you didn't like about it?

[martin goodall]

This may be a complete cop-out, but I figured out that the cramped nature of the goods yard on my Burford layout (and the fact that the back road of the yard continues through gates across the station yard into the brewery) provides a perfect excuse for an 'official ban' on loose shunting into this yard. If you want an explanation for this, one might assume that a shunter once failed to catch a couple of loose-shunted wagons in time to pin the brakes down, and they went sailing on, demolishing the yard gates and giving one of the brewery dray horses the fright of its life.

I imagine that there would be a note to this effect in the Divisional Appendix, or even an annotaion on the Service Timetable for the branch. ["Wagons must not be loose shunted into the goods yard at Burford, but must remain coupled up to the locomotive until brought completely to a stand at the position where they are to be left, whereupon the brakes must be securely pinned down."]

I did consider erecting a 4mm-scale sign by the yard point:

GWR
WAGONS MUST NOT BE
LOOSE-SHUNTED INTO
THIS YARD
BY ORDER

but I imagine the powers that be would have relied on the written instruction in the Divisional Appendix, plus local knowledge, so the sign has not been erected.

I have no idea whether anything of this sort ever happened in practice, but there must surely have been some circumstances in which loose shunting of wagons was not permitted for reasons of safety. Anyway, I plead this as justification for shunting my wagons to a stand at Burford before they are uncoupled.

[Tim V]

Good try Martin, however the nearest equivalent I can think of "Hemyock" did loose shunt - through the gates and across the road as well! See "Western Steam in Devon and Cornwall" by Michael Welch.

I think the flywheel idea is a non starter ( ! ). The whole point is to keep the wagon under control. So by using F3 - slow speed, plus asymmetric DC to slow and stop the wagon, it should be possible to properly shunt, though unfortunately not to the extent of Tony's video

[Dave K]

This is loose shunting. It can be done in DCC. Onboard uncouplers, I'm using S&W couplings - an etch came my way - it's the Mk1 version. The delayed action is not needed as the uncoupling is in the wagon.

Tim,
Can you provide some more detail about the components you have use, i.e. what DCC decoder and the origin of the white metal wagon.

[Andy W]

I love the video of the Daffodil run that Tim posted. A lost world - what a tragedy.

[Tim V]

That's an ABS kit.
Just standard decoders, I use either Zimo or Lenz.

It is a lost world, and only 1964 - but it is now 47 years ago. 47 years before that was 1917, the First World War was in progress, and look how much has changed since then.

[Tim V]

Two days till ExpoEM, and I'm frantically gluing together an E129 B set courtesy of Comet, I thought you might like to see a picture of the clamps used to hold the coaches together!

IMG_3186.JPG

Yes adapted wooden clothes pegs

[Mike Garwood]

Hi Tim,

OK, I'll bite - how did you build them. If those are Comet sides did you paint them BEFORE gluing the roof on? And if you did, I have to ask why?

I'm only sorry that I shan't make Expo this year as I'm holding the fort in work, have a great show.

kindest regards

Mike

[Tim V]

I detailed the building of these coaches on the old RMweb, see http://www.rmweb.co.uk/community/index. ... t-working/
as to why I can't give a link.

The sides were built with hinges and handles "in the flat", then soldered to the ends, then painted. Finally the roofs were glued on. All shown on my RMweb workbench, now apparently off line.

[grovenor-2685]

NWSL made a boxcar with such a flywheel for this very purpose, I did once try to fit it in a brake van but I didn't find it satisfactory, maybe it needed more perseverance. But then its not in the current catalogue so maybe it didn't work to well for them either. The parts must be in one of my bits boxes.
regards
Keith

Can you remeber what you didn't like about it?

I seem to have missed this question, sorry. I think it was most likely that I had unrealistic expectations from the advertising. I was hoping that it could be given a little push and would drift gently along. But in practice to get the flywheel rolling took a slow and gentle acceleration, otherwise the wheels just skidded, then it rolled nowhere near far enough. The flywheel has pinpoint bearings but the rubberband drive i suspect had quite large losses.
Regards
Keith

[Tim V]

On my work bench is my test track

My ROD's tender derailed when being propelled on the curve in one particular spot. Ah I thought, it's facing the wrong way - the curve should go the other way. Turned the ROD round, and guess what, the tender fell off in the same place

Mutter, mutter, track (C&L flexi) looked OK, no dog legs or kinks. More muttering, must try and finish that ROD.

I eventually concluded the track must be undergauge, found an old parallel S4 society gauge - it was!

Went round the track pushing the rails out under finger pressure. Couple of creaks later, retried ROD - works perfectly.

Moral - never assume anything.

[Tim V]

Hi Tim,

OK, I'll bite - how did you build them. If those are Comet sides did you paint them BEFORE gluing the roof on? And if you did, I have to ask why?

I'm only sorry that I shan't make Expo this year as I'm holding the fort in work, have a great show.

kindest regards

Mike

Archive RMweb back on line, details of the coach on this thread
http://www.rmweb.co.uk/forum/viewtopic. ... &start=125

[Tim V]

Been busy with another Bachman 45xx.
Discovered the wheels I'd bought only had 9" crank throw, as opposed to the 12" they should have. As this was supposed to be a "quickie", I baulked at £62 for Ultrascales, and decided to modify the Gibson's I'd bought. I won't show the jig I made.

IMG_3989.JPG

Here I'm assessing the work needed to adjust the coupling rods. Note the huge offset on the middle crank hole, this will never give smooth running.

IMG_3988.JPG

[martin goodall]

Please keep us informed of further progress on this one, Tim. Having retired 'hurt' from my first attempt to convert a Bachmann 45XX, I am keen to learn all I can of others' experience in dealing with this particular beast.

[Tim V]

So what went wrong Martin?

[martin goodall]

I posted a note on this webforum on 9 Jan 2010 (in a thread entitled "Re: Bachmann 45xx conversion") in which I recounted the problems I had with the conversion of this chasis. This is what I wrote:

"I made an unsuccessful attempt last week to convert a Bachman 45XX to P4 using the Ultrascale conversion set.

Testing of the Bachmann chassis before conversion proved conclusively that it ran smoothly and quietly, but after conversion (which turned out to be less than straightforward in the absence of any instructions - even the data sheet on the Ultrascale website was of no practical use) there was a distinct 'knock' once in every revolution of the driving wheels, and the model occasionally stalled altogether, and had to be switched off quickly to avoid burning out the motor. It was so bad on one occasion that the (pre-set) quartering went.

On inspection, there were definitely no clearance problems between the cross-heads and the crank-pins on the leading wheels; there was ample room here and no possibility of fouling. I tentatively concluded that the problem is either (1) an eccentric or inaccurately cut brass gear wheel (although this seems surprising, bearing in mind the usually excellent quality of Ultrascale products) or (2) excessive slop of the re-used Bachmann coupling rods on the crankpins (especially those on the leading wheels - where the crankpin measures 2.0 mm, whereas the hole in the coupling rod measures 2.3mm diameter - (or possibly a combination of both). But I am not sure why this should cause the mechanism to stutter so badly and to seize up altogether sometimes.

The Ultrascale gear wheel came under suspicion because, when the rods were removed so that the centre wheelset alone would be turned by the motor, a distinct change could be heard in the note from the motor once in every revolution of this axle, accompanied by a slight 'graunching' sound (also once in every revolution of the axle). However, I don't think the gear-wheel can be held responsible for the derangement of the quartering, which must have been caused by the driven (middle) axle continuing to turn when the leading axle had seized up for some other reason.

Substituting the original Bachmann nylon gear in place of the brass gear wheel supplied by Ultrascale is no longer an option, because the problem I had with the quartering, which once it had slipped kept going out of adjustment, led me to pin the wheels to the axles, using the generous moulded bush on the backs of the wheels, so that the wheels are now well and truly fixed to their axles.

Replacement of the Bachmann coupling rods might be part of the answer, but before seeking out an alternative set of rods, I would be interested to hear whether anyone else has encountered problems with this conversion and, if so, how they resolved those problems.

Subject to any comments, I am currently thinking of fitting a new set of wheels, using the Bachmann nylon gear wheel for the final drive, and a new set of coupling rods, making sure that these are a close running fit on the crankpins. The other option might be to bush the Bachmann couplng rods to achieve the desired running fit on the crankpins."

Subsequent exchanges within that thread made it clear that I was not the only person who had encountered these problems with the 45XX. These exchanges in fact showed that the business of converting Bachmann locos is not so simple and reliable as people seemed to think it was.

In view of the very helpful suggestions that had been made by other conributors to the thread, I decided to see if I could devise a way of checking the casting of the Bachmann chassis block on my 45XX. My usual method for checking that loco chassis (or frames and axle bearings) are accurately aligned is to insert long lengths of axle rod (each about a foot long) through the axle holes/bearings. If any of the holes/bearings are out of true this will immediately show up, as it can clearly be seen whether or not the long lengths of rod are parallel with each other and level. The rods I usually employ for this purpose are 1/8-inch, but I have now invested in some similar lengths of 3mm rod for use with Bachmann chassis.

This project was put on the back burner for some considerable time, but I have subsequently obtained a set of replacement wheels and motion, and this time I am going to re-check the trueness (or lack of truth) of the alignment of the centre axle slot in the chassis casting very carefully, as I suspect this was at the root of the problem. However, my second attempt at the 45XX is not imminent, and so I shall follow Tim's current project with interest.