Two different motors in one loco!

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RobLeighton
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Two different motors in one loco!

Postby RobLeighton » Mon Apr 19, 2021 10:46 pm

Just picked up an old Fobbi (Jouef) Bb22200 electric loco from the 80s I think, cheaply on eBay.
It's in okay condition but didn't run at all well on first test.

When I opened it up I discovered a vertical motor on one bogie and a pancake on the other, wired together !!!
Brush springs were trying to escape on the pancake but after bending the clips back in on them they are fine again.

Bit of lubrication and it's running pretty well now...
Strange motor arrangement though!

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Ironduke
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Re: Two different motors in one loco!

Postby Ironduke » Mon Apr 19, 2021 10:48 pm

Photos please.
Regards
Rob

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Bufferstop
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Re: Two different motors in one loco!

Postby Bufferstop » Mon Apr 19, 2021 11:16 pm

Did you try running it on each separately. I too would like to see a photo of the two bogies. The arrangement in most old Lima locos might lead to someone thinking that the trailing bogie was something like a Tenshodo SPUD bogie. It's just a rather heavy block containing the pickups for one rail. I have a Jouef BR "Peak" which despite the length of their six wheel bogies still manages to have about one third of the motor overhanging the rear of the bogie.
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Bigmet
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Re: Two different motors in one loco!

Postby Bigmet » Tue Apr 20, 2021 9:34 am

RobLeighton wrote:...When I opened it up I discovered a vertical motor on one bogie and a pancake on the other, wired together !!!...
Strange motor arrangement though!

DIY job to improve pick up and traction. If done optimally, it allows all metal driven wheels for reliable pick up and as much of the model's weight as possible on the driven wheels so that the foul bodge of traction tyres can be cast into the outer darkness where they belong.

It came as a big surprise to me when young that a twin motor bogie model had about 3x the traction of the single motor bogie model running in the optimal direction (motor bogie at trailing end of the loco when pulling a train). Once I started the physics course all became clear, all the model's mass on driven wheels, instead of near half the model's mass on Triang's 'no roll' wheels acting as brakes, a constant thief of traction. (It should be near 4x the traction for the same model mass, all wheels driven, but the losses inherent to a pair of worm drives on the two independent motors lose some of the potential. Spur gear drive motor bogies are better in this respect, they more readily take up the small mismatches between the motors.)

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Mountain
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Re: Two different motors in one loco!

Postby Mountain » Tue Apr 20, 2021 10:25 am

I almost bought a Trix prototype model locomotive of an A2 that had a motor drive in both the tender and on the loco. The reason for this was that as a prototype model (Which it was really well made) it had to be appraised and they needed to see both drive units at an ppraisal so when the model went into production (I don't believe the A2 ever made it into prodiction with Trix?), they would need to decide to make them in loco or tender drive form.

The shop owner wanted £100 and it was around 20 years ago. As a novelty it was interesting, but as a BR blue era modeller at the time, I was not sure I wanted LNER on my model railway. I was assured that it did run well and it was a very weighty loco made out of metal.

I went back to see it a few times as I was very tempted, but I did not buy it, as I was into my B.R. blue diesels at the time, and it was in the days when Bachmann were coming out with their class 46, and Lima had many fine models in B.R. blue to tempt me. (A few years prior to this, there had for a few years been a B.R. blue shortage of new models, hence why it was a scramble to get them while they were available, as the model world was concentrating their efforts in providing new privatization liveries).

Bigmet
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Re: Two different motors in one loco!

Postby Bigmet » Tue Apr 20, 2021 11:24 am

Mountain wrote:I almost bought a Trix prototype model locomotive of an A2 that had a motor drive in both the tender and on the loco. The reason for this was that as a prototype model (which was really well made) it had to be appraised and they needed to see both drive units at appraisal...

OF course Roco have this licked nowadays, motor in tender driving both the tender wheels and via a drive shaft the loco wheels. No more the sight of the mighty tender shoving along a loco with its drivers locked by snagged side rod...


Mountain wrote:...I don't believe the A2 ever made it into production with Trix?...

It was produced, but quantities were limited. It was the easily the best RTR OO loco available, an LNER pacific for a start, and then all flanged wheels, dimensionally good, ran and pulled like it should, well detailed by the standard of the day. (I have probably mentioned my frustration in my youthful days before credit cards when HA Blunt was strictly 'cash on the nail', and nothing could be reserved or ordered by kids: they had one in stock, but between seeing it in the window and cycling home and returning with the money, some other lucky person had bought it. So I used the money for a BEC J17 kit, and the Trix A2 would be my last potential RTR OO purchase until Replica made a rather nifty B1.)

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Mountain
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Re: Two different motors in one loco!

Postby Mountain » Tue Apr 20, 2021 2:24 pm

I I can imagine that the twin motor A2 prototype would be able to outpull almost anything else as this was made like the old Hornby dublo products were except it had much finer made mechanisms.
Were the ones that made it to production loco or tender drive?

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Re: Two different motors in one loco!

Postby Bigmet » Tue Apr 20, 2021 3:02 pm

Most of the production Trix A2's were I believe loco drive; certainly the case with the one I saw operating on 'Havil' in the 1960s (de Havilland MRC's big layout, which still exists in slightly reduced form and is operable) and of course as seen on the BBC's famous 'Blue Peter' layout.

But according to the Trix Collector's club, there were some produced with tender drive. Follow the link for more.
http://www.ttrca.co.uk/A2%20Peppercorn%20Servicing.pdf

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luckymucklebackit
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Re: Two different motors in one loco!

Postby luckymucklebackit » Wed Apr 21, 2021 10:20 am

Perhaps my memory is playing tricks on me, but I am sure that Trix also marketed their Westerns as being available with two motors,

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Bigmet
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Re: Two different motors in one loco!

Postby Bigmet » Wed Apr 21, 2021 11:35 am

That's clearly feasible from the assembly diagram, the bogie frame is the same on the trailing bogie as the powered, so with the motor and other fittings both could be powered.
http://www.ttrca.co.uk/D1000%20Class%20-%202%20Rail.pdf

Trix was a class act in terms of product design, the weaknesses appear to have been distribution, and manufacture of sufficient product. I have one Trix product left, a pair of their Commonwealth coach bogies moulded in a super slippy polymer. Like an idiot I sold all but this one pair decades ago never realising we should not see their like again... Whatever, now equipped with stainless steel pinpoint axle MGW coach wheels, and the coach that has them is the most free rolling item on the layout, used as a simple 'unintended gradient' detector. (Even the old way undersize wheels have been repurposed, turned down slightly to make 10mm diameter wheels for the diamond frame bogies of an LNER 'Sept' bogie bolster.)

And then there's the ex-Trix A4 body and tender mouldings, still being retailed as the basis of the Bachmann A4. That's some testament to the tooling quality, both for capturing the tricky body form and still usable.

In case it is of interest, the TTRCA front page, well worth a browse. http://www.ttrca.co.uk/

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Bufferstop
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Re: Two different motors in one loco!

Postby Bufferstop » Wed Apr 21, 2021 1:18 pm

Weren't the Trix locos built to a slightly odd scale around 3.75mm/ft?
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Bigmet
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Re: Two different motors in one loco!

Postby Bigmet » Wed Apr 21, 2021 3:04 pm

Variable scale even! My understanding is that Trix' UK OO product introductions of the 1950s were usually 3.8mm/ft - then quite common in contemporary HO - and progressively 'slid' to 4mm/ft in the 1960s. (This 'variscale' within a range was completely normal amongst European HO manufacturers.)

The Commonwealth bogies I have are 33mm wheelbase, which against the prototype's 8'6" wheelbase indicates 3.9mm/ft was used. The Peppercorn A2 and the Gresley pacifics were 4mm/ft.

For comparison, I recall a long ago very amusing letter in which the Triang Hornby B12/3 was shown to be a net 3.8mm/ft model on the length dimension - for no readily apparent good reason, 8mm had been deducted from the frame and boiler length between the front driver and the bogie.
The tender however was probably the best tender T-H had then produced, a 4mm/ft scale model in all respects, apart from T-H's then necessary added 2mm of height to clear their monster tension lock; this easily rectified because all the height gain was above the tender axlebox spring hangers. Back in the day I gave several the cut down treatment to fix this, and detailed them, and the last one I have still looks well and awaits the construction of a J19 or 20 to go with: I have yet to decide which.

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luckymucklebackit
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Re: Two different motors in one loco!

Postby luckymucklebackit » Wed Apr 21, 2021 4:06 pm

Bufferstop wrote:Weren't the Trix locos built to a slightly odd scale around 3.75mm/ft?


Certainly in around 1969 I had five Triang-Hornby Mark 1 coaches and two Trix Mark 1s and the difference in height was very noticeable, the Trix coaches looked to be about 5mm lower at roof height (possibly more - its a long time ago). Coupling differences aside, you couldn't have run them together without it looking very odd indeed.

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RobLeighton
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Re: Two different motors in one loco!

Postby RobLeighton » Wed Apr 21, 2021 4:24 pm

two-motors.png


Here's a photo - if it's a Frankenstein job it's a very good one, the bogie plastics seem to match!

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Bufferstop
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Re: Two different motors in one loco!

Postby Bufferstop » Wed Apr 21, 2021 5:19 pm

At a guess I would say at one point the manufacturer swapped from one design to the other, and someone made use of a spare motor bogie to do a quick upgrade. They probably added the ballast weight as well.
luckymucklebackit wrote:....in around 1969 I had five Triang-Hornby Mark 1 coaches and two Trix Mark 1s and the difference in height was very noticeable, the Trix coaches looked to be about 5mm lower at roof height .........


A combination of two effects here, first you have to contend with the Trix odd scale, then you have to deal with the history effects of peculiar running gear produced by Rovex. When Rovex got started everything including driving wheels was produced in plastic. The original Rovex locos had plunger pickups riding on the rail tops. This lead to massive flanges and wide tires on the rolling stock. By the time they had Morphed into Triang the plastic driving wheels had gone but the rolling stock was still using the same wheels, which were moulded with hollow half axles and fitted on a steel pin. One wheel was free to slide on the pin the other was kept in place by two small splines on the pin. The whole lot was free to slide from side to side in the axleboxes. This gave them a variable back to back dimension which was needed to get the wheels through a workable set of points. The wheels were just about 10mm diameter which was compensated for by introducing an extra 2mm between the axle and buffer heights. This dimension was carried forward through almost ever item designed and produced at Margate. Even the all nylon chassis for goods wagons and the 4wheel coaches had it, maybe still does. It's mitigated in their coach stock by fitting approx 12mm instead of 14mm wheels in the bogies. it's most notable if you find an item that they gained from Hornby-Dublo via Dapol and Wrenn which had been modified to take tensionlock couplers but had their buffers at a more scale correct height.
I had a purge of my stock, at one point, using whatever methods I could to get all buffers at approximately the correct height. This meant re-wheeling some items, and replacement bogies to get rid of the huge coupler and giving the grand kids most of the four wheeled items which had an expanse of shiny black plastic below the buffer beam. Everywhere you look on my layout you will see grounded bodies from chassis which were just too much of a faff to upgrade. My wiring system is based on distressed Oxo, Kit Kat and Ffyfes vans with a big hole in the floor to hide my connector blocks, much easier than screwing them to the underside of the boards.
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