American method for pickups

[HowardGWR]

I have already searched the existing references to this subject but i am still lacking the information I need.

First one makes sure the rims of the wheels on one side transfer current to the frames via the axle. Usually, as we use plastic centered wheels, one would use the 'shorting wires' provided by Bill Bedford and others. The other side's wheels remain insulated and must never come in contact with the frames.

Next one does the same with the coupled vehicle (usually the tender but for a tank engine has to be something other, we GWR types usually have a shunters' truck coupled to ours).

There must be no electrical contact between the engine and said coupled vehicle.

One then runs a wire from the engine's frame to the motor and from the other contact on the motor one runs an insulated wire from it to the frame of the coupled vehicle (assuming it's metal or can be 'metalled' in the same way as the engine and contacted with the wheels on one side, that side being opposite to the one on the engine). This wire can be disguised as a water feed hose, if a tender, or a vacuum hose, if a truck or coach.

Have I got this right?

If so (phew!) it will be the first complete description of this method I have ever read, since it leaves me in no doubt as to what must be done.

We electrical illiterates need it that simple.

[nigelcliffe]

Insulate the buffers and couplings. Otherwise, sooner or later, you will buffer up to something else wired up "American" and a short circuit occurs.

I've read of people annealing (removing the spring from wire) their AJ couplings in a long rake of wagons with that mistake.

"American" works OK if vehicle bodies are plastic, though I wonder why one would choose to sacrifice half the pickups on a loco.

[Tim V]

I think you have summarised the system, I'm trying to think how I came across it, it was a very long time ago.

It is useful for tender locos, but I wouldn't recommend it for tank locos. Split axles should be used there.

As for "why", well it eliminates wiper pickups - which is no bad thing.

Why are wiper pickups a "bad thing". High maintenance, they wear out, they are unsightly, they impose friction.

I'm surprised at your comment Nigel, especially with your interest (!) in the 2mm society

[nigelcliffe]

I'm surprised at your comment Nigel, especially with your interest (!) in the 2mm society

Which comments surprised you ?
Avoid short circuit paths ? Try buffering up two "American" pickup metal locos.
Fit pickups to every axle if you can ?


And where can I find details of this "2mm society" you mention ?

- Nigel

[martin goodall]

If you are going to go to the trouble of shorting out the wheels on one side, then why not go the whole hog and do it on both sides, add split axles and split the frames? (I have never done this myself, but understand that there are two methods - one involving insulating one frame from the other with gapped double-sided copper clad paxolin spacers or other insulated spacers [e.g. tufnol blocks], or altermatively, as on 'Adavoyle', insulating around each axlebox by sawing through the frame and injecting Araldite, but they use thick frames on the 'Adavoyle' engines, which is what makes this feasible - not sure it would work with thin frames).

As regards the buffering up problem, double-heading is fairly rare for most of us, and I imagine that the vast majority of the carriages and wagons we use have fully insulated wheels on both sides nowadays, so shorting through the buffers seems a fairly remote possibility if using the 'American' system.

I have never heard of anyone applying the 'American' system to tank locos, relying on the leading vehicle for pick-up off the other rail. I can see practical problems - for example, you wouldn't want to include a shunter's truck in the make-up of the branch passenger train.

[HowardGWR]

First thanks to all posters and so prompt too!

I already did the split frame split axle method and it worked fine with a plastic body but with my whitemetal pannier it was a nightmare. When I asked an expert at a show, he started talking about using sellotape under the body and I began very rapidly to lose interest. Does anyone have good, easy to achieve, ideas about keeping the split frame away from the metal body parts? What one does with outside cylinder (made of n/s or brass) engines which cross the frames as a saddle I have no idea. Any tips there most welcome.

On the Adavoyle system, I simply cannot envisage what is described Martin. Could you attempt it again please? (Sawing through frames -which way, for instance?). Perhaps there is a photo somewhere?

As far as the tank engine with American, my model tanks will never be on their own on the visible layout as I just want to run stuff up and down the diorama. There is a siding into which a coal wagon will be shoved, but this will always be done by the Bristol East Depot shunter, which will always have its shunter's truck attached, because it's the shunter who is the WRO man in charge. Adrian Swain has even provided him with his ABS kit!!

Tank engines on trains will simply feed through to the attached coaches, as though they were tenders. Plenty of return wheels there. American has the advantage over split axle, split frame, in that there is far less engineering to be done ITSTM. In fact none on the frame.

[HowardGWR]

Correction WRO should read WLO (wrong line order).

[nigelcliffe]

First thanks to all posters and so prompt too!
I already did the split frame split axle method and it worked fine with a plastic body but with my whitemetal pannier it was a nightmare. When I asked an expert at a show, he started talking about using sellotape under the body and I began very rapidly to lose interest. Does anyone have good, easy to achieve, ideas about keeping the split frame away from the metal body parts? What one does with outside cylinder (made of n/s or brass) engines which cross the frames as a saddle I have no idea. Any tips there most welcome.

Sellotape is an insulator, so works fine. Other possible methods include paper, masking tape, paper soaked in cyno-acrylic, varnish, shellac, epoxy resin (home made tufnol?), arranging body mountings so the frames are just short of the body, etc.. I think I've used most of them.

Another approach is to make frames from printed circuit board and gap it so there is only conductivity when required, though I would be concerned about flexibility along the length of 4mm scale frames without additional bracing. It works well in 2mm scale.
An approach I've not tried might be to use a layer of thin double-sided PCB (I have some which is 0.3mm thick) to attach hornblocks/bearings, thus connecting those bearings/hornblocks to a small area of PCB, rather than the entire frame.


Cylinder gear which crosses a chassis is a problem with split-frame. The only answer is to think through the places for insulation and build those in as you go. If 100% certain that rods never touch wheel rims, then plastic wheel centres mean that rods are insulated from the wheels, and the only contact with the frames are where the cylinders attach to chassis. So, sub-sectioning a chassis might be an answer.



( And I have shorted through a plastic wagon; metal couplings to metal W-irons and a wheel which brushed the W-iron. On its own, not a problem. In conjunction with another path to track it led to a short. I now try insulate coupling mounts wherever possible).

- Nigel

[martin goodall]

On the Adavoyle system, I simply cannot envisage what is described Martin. Could you attempt it again please? (Sawing through frames -which way, for instance?). Perhaps there is a photo somewhere?

See Railway Modeller JAN, FEB, MARCH and MAY 1982 (a comprehensive 4-part series).

[HowardGWR]

So Nigel, if I have a w/m shunters truck I must ensure that I somehow not allow its metal bits to come into contact with the loco's metal bits (couplings, buffers, etc).

Hmm, this is beginning to sound like the sellotape expert who put me off split axles with a metal engine body. I cannot begin to imagine how I could achieve it. It was very unlucky your coupling hook came into contact with your suspension on the plastic wagon. I suppose the coupling was sprung and sprang back!

I wonder if there is a plastic shunters truck available?

As said earlier there are only 4 wheels on the truck (two to pick up or set down, as it were) so perhaps I ought to go back to wipers. I don't get on with wipers and they seem to interfere all to easily with the suspension forces. (getting technical now).

Martin, thank you for the reference. A blast from the past. I did look up the Internet references but could only find pretty pictures. Given the layout's fame I was amused to see the hand of God appearing after a derailment on the YouTube film. Hope for me yet. I shall have to see if I can find those issues - all four issues dealt with split frames?

[nigelcliffe]

So Nigel, if I have a w/m shunters truck I must ensure that I somehow not allow its metal bits to come into contact with the loco's metal bits (couplings, buffers, etc).

Hmm, this is beginning to sound like the sellotape expert who put me off split axles with a metal engine body. I cannot begin to imagine how I could achieve it. It was very unlucky your coupling hook came into contact with your suspension on the plastic wagon. I suppose the coupling was sprung and sprang back!

What you choose as a solution is your choice. I am reporting possible short-circuit paths, some of which I have experienced. Others say they don't happen to them. I've given a list of insulators, some are very thin, such as fag paper (with or without adhesive soaking).

How to deal with a white-metal wagon ? Depends on where there is clearance, and how much pickup you require from it. Would you accept inside wheel bearings (non prototypical in most cases), or must it run only on the outside W-irons ? If only the outside W-irons, is there a way to fabricate those in an insulated manner, or insulate them from the rest of the model ? Or, is there a way to fix the headstocks so they are insulated from the body ?


My wagon short was very simple to prevent if I'd thought about it. Etched U-section W-iron (Bill Bedford, but anyones can do this) carrying the wheels. Rest of wagon is a plastic kit. A wheel rim could touch the W-iron because something had been knocked/bent out of alignment and the wheel was fractionally wonky. The coupling was fixed to the centre of the W-iron. Result, an intermittant electrical path from coupling to rim.



- Nigel

[HowardGWR]

Nigel - No first Martin.

I looked on eBay at the issues you mention, of RM for 1982, but none of the descriptions of articles therein mentioned Adavoyle. Are you sure you gave the right year?

Now Nigel.

I had another look at my shunters truck ABS kit and pondered substituting the end to be coupled with the engine in plasticard. The w/m buffer beam is so beautifully cast I could not bear to change it and saw that I was making too much of a simple problem. I shall coat the buffers with a thin film of something (thanks for your suggestions) and use a plastic coupling hook from the loads of Coopercraft and similar items i have in my spares box. The coupling, hmm, I'll try experimenting with a slice of biro refill for the last link, nobody would ever notice I'm sure. I was not planning to try and compensate the truck as it only has a 7ft wheelbase. Adrian Swain points out a very good way of carving a slot in the bearing and I am sure this will prevent any chance of the insulated wheel rim touching any of the bodywork.

Unless there are further thoughts (and I hope anyone who has one will take the trouble) I will now get on with it!!

[martin goodall]

To answer Howard's queries about the articles in the 1982 Modeller, the articles in question did not mention Adavoyle as such, but that was the layout for which the locos described in those articles were built.

All four articles formed a single series on scratch-building a fleet of P4 (21mm gauge) locos with split frames [or, to be more accurate, insulated hornguides], fully sprung suspension and tender-mounted motors driving through a cardan shaft onto the middle axle of the loco - all quite revolutionary stuff at the time, but having seen these engines in action, the results certainly justified the methods used. I never once saw one derail, and the smoothness of their running had to be seen to be believed. They have never been bettered in 4mm scale.

[HowardGWR]

Many thanks Martin. I will certainly look out those when i get a chance. Right now I am putting together an 'American' mainframe for a 57xx for which I am going to use the shunters truck, to which it will be permanently coupled, as the return method.

I get the impression I may be the first to try (???) and will post how it goes when there is something to report but, meanwhile, I believe the Internet expression is 'going dark'.

[Paul Willis]

I get the impression I may be the first to try (???) and will post how it goes when there is something to report but, meanwhile, I believe the Internet expression is 'going dark'.

"Going dark" may be the best way of chasing out that elusive short that everyone has been worrying about... Turn the lights down and look for the blue spark!


Flymo

[HowardGWR]

Well I've done it. A small step for modelling but a giant leap for Howard.
Enclosed hopefully is a photo of the bare mechanics and I hope people find this at least interesting. The experiment was, if you remember to overcome the problem of not being able to use the American method of pickup on a tank engine by, in the case of non light engine movements, using a shunters' truck as current return device.
After many years of resuming the armchair, I have taken the plunge and you can see my entry for the armchair modellers' competition, kindly organised by Terry Bendall. It's on nearly every photo of the prize giving at this year's Scaleforum (see retrospective photos).
That model is to be expanded to an entire river bank scene from which the modelled pump house and softening plant gets its water. A shunting engine would set off from Bristol East Depot with a loco coal wagon and would work under wrong line order to drop off its load and pick up the empty before returning to the yard wrong line. This is the only shunting manoeuvre that will take place on my layout and always took place with a shunting truck. All other movements are with trains.
So I can use American method on the tank-hauled trains using the coaches or wagon wheels and just this one side show using the shunters' truck.
The truck is a w/m ABS kit and after examination I decided to use a compensation underframe setup so as to keep the insulated wheels on one side well away from the w/m sides, etc. Trapped in their cage they are safer. I had to do a load of filing away of w/m around the area of the kit axle guards to give enough width for the compensation frames as the kit metal with solid axleguards (for safety of shunters) is a bit hefty, but that is good for road holding of course and road holding is what I was aiming for so that current would always be passed to the rails. I've indulged in the purchase of some jigs. One is the Brassmasters wheelbase setting gauge which was useful when gluing down the compensation units to the wagon floor with the axles in their bearings. The other I got through the NWSEMGAG which is to ensure that the wheels are not only in gauge but equally distant from the ends of the pin point axles - clever stuff. This should all help to stop the short wheelbase truck (7 ft wb) crabbing along the track.

Turning to the engine, I dismantled the split frame 57xx (that's a type of GWR shunting engine) and substituted non insulated axles and ditto spacers. What a relief not to have to worry about all those cross frame shorting issues. I was able to keep the Perseverance frame square and not moved between axle distances by doing everything one at a time. Thus hopefully the axleboxes would keep their distances to match with the coupling rods that had been matched all those years ago with the special jig that ensures the crank pins snuggle into the coupling rod joint holes perfectly. I think that was a Perseverance item too. I admit I knew I was on a gamble here with all that unsoldering and re-soldering.
Having quartered by eye and losing the usual crankpin nut to the carpet (Sharman item made of steel, but the magnet could not discover it in the tufts) I then assembled the Sharman wheels using a spare Ultrascale nut I had for another kit (note to reorder one nut, perhaps several to be sure). The Portescap MJT gearbox sends the motor down the boiler out of the way of the backhead. I left the grub screw on the gearbox toothed wheel loose at this stage. One side of the Portescap 1219 is connected to the frame via a soldered stud fastener (MJT idea?) and the other was replaced with a longer wire which I made long enough to reach the shunters' truck.

Now to test. I touched the long wire onto the track first and the motor revolved. Great!
I then touched the wire onto the truck frame, having remembered to turn it round the right way. Remember the shorted wheels must be on the opposite side to the ones on the engine. Drat, I forgot to mention that I had removed the Bill Bedford shorting wires from three of the six Sharman driving wheels on the engine on the off side and I attached two new shorting wires (ones with 2mm centres) to half the four shunters' truck wheels on one side which of course has to be the near side in that case.
Nothing happened. After a moment's thought I touched the wire onto the rim of the shorted wheel and the motor turned. So clearly the current was not getting through from the truck frame to the rim of the shorted wheel. So I looked at the shorting wires on the two 2mm axles and concluded that the little grips on the circle that goes around the axle (these were from the combined one eighth in and 2 mm shorting wire fret from EMGS stores) were not gripping! So I soldered them up to the axles and tried again, plonking the wire from the engine on the frame of the truck.
Bingo, the motor revolved. Full of hope and trepidation (it's exciting this modelling) I tightened the grub screw on the driving axle and reapplied the current from the ECM controller. To my serendipitous amazement the whole shebang moved effortlessly up and down the test track. You will notice in the photo that I had bits of blue tack at strategic points to ensure no contact between the vehicles and I also kept the 1219 Portescap motor away from the frame as I have no idea what happens if they touch (I just do not understand electrics which is a big drawback in this hobby and explains my choice of a tail chasing layout).
The pick up and sure running is something I have never experienced since I took up this game in 1986 and was led astray by all those articles in MRJ.

I have one more comment. Those are EM wheels on the engine and I am not throwing away all that investment I made years ago in those many lovely wheels awaiting to go on my 29xx, 40xx, etc. So another member joins the EMF sub group of Martin Goodall. Whether we shall be banished from S4 shows I know not, but that's the way it's going to be on Foxes Wood Pumping Station, (fighting talk).

I've bought lots of P4 wheels too and will standardise on those in future so it will be a challenge to see if anyone notices as the Cardiff to Portsmouth rushes through with 5 on.

Regards, Howard

[HowardGWR]

Correction. The non-shorted wheels on the engine are of course on the *near* side.