I am in the dark about Split Chassis locos

[Jimbo1707820979]

Please advise. I recently bought a nice little N2  Mainline loco and took it to my dealer for Hornby chip fitting. Nasty surprise ☹️.  I was told it was a split-chassis model and thus very hard to convert to DCC. Therefore expensive (more than I paid for it ).

Is there any guide as to when Hornby /Bachmann et al. stopped making split-chassis locos ? (If indeed they stopped !) Also how do you recognise these ?  As I would like to avoid putting my foot into this particular cow-splat in future, if possible. There doesn't seem to be much mention of "split-chassis " in advertisements or literature.  Anyway, seeing my look of dismay the kind dealer said "leave it with us, we'll have a look at it".

[Chrissaf]

There are plenty of YouTube videos on converting 'split chassis' locos.

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Without taking the loco apart, I believe one clue to a loco being a split chassis, is that they typically have the phosphor bronze pick-ups on the backs of the wheels on one side ONLY. This is because on the other side, the wheels are in electrical contact with the metal chassis, and the motor connection on one side is also made to the chassis. As an analogy, think of the chassis as being an earth return.

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Don't have any split chassis locos myself, so my statement may be over-ruled or corrected by others with practicable experience.

 

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[poliss]

Here's how you fit a decoder to the split chassis. You can see why it's more expensive to have done professionally.

http://www.mrol.com.au/Articles/DCC/SplitChassis.aspx

[Jimbo1707820979]

Many thanks, poliss and Chrissaf for your usual excellent advice. The link to the article in Model Railways On-Line was really useful and has forewarned me about buying split-chassis locos !  It appears that just a few by Mainline and Bachmann are involved so it will now be a case of Buyer Beware. Glad to see that Hornby are not making these and I now understand why the Hornby N2 commands a much higher price, having an updated 5-pole motor and being DCC ready. We live and learn ! 😳

[Chrissaf]

Looking at Poliss' link. It may be, if I understood the article correctly, that another indicator for a full 'split chassis' loco design is having no back of wheel 'phosphor bronze' wipers at all.

[Rog RJ]

I don't think Hornby ever made split chassis locos.  Those Hornby and Triang models with pickups on one side only are live chassis models.

[Ruffnut Thorston]

Looking at Poliss' link. It may be, if I understood the article correctly, that another indicator for a full 'split chassis' loco design is having no back of wheel 'phosphor bronze' wipers at all.

 

The "pick-ups" arrangement can indeed vary.

 

Some non-split chassis models have two sets of wipers...E.G. the Hornby BR 9F 2-10-0 locos.

 

Some have wipers on only one side...E.G. older Tri-ang Hornby Type locos. As you said above, these use the chassis and axles to get the electicity from the motor to the "other" rail. (Earth.)

 

Some Hornby Ringfield Tender Drive locos also have no wipers at all. The "positive" feed to the motor being via the loco wheels (one side) and chassis to a metal "wiper" on the loco to tender drawbar, that contacts with a metal pin on the tender.

This is wired to the motor.

The "return" is via the motor block, the axles, and the "other" side of the tender wheels. (The side without traction tyres...)

 

Some models use concealed plungers, that bear onto the back of the live wheels, sometimes on both sides. These are harder to spot.

 

If you can see the driving wheel axles on a split-chassis loco, they are in two halves, with a plastic "bush" joining them. Often the driving gear is moulded onto one of these bushes.

 

The electricity is conducted from the wheels to the half axles, and via the "bearing" surfaces, to the chassis halves. (The two halves of the chassis are seperated by plastic insulating pieces.)

 

The motor is connected to the chassis, one "brush" to each side of the chassis. This completes the circuit, sometimes no wires are used at all!

 

I think that most split chassis British Outline models were made by first "Mainline" (Palitoy), and later by, possibly "Replica Railways" (mostly ex Mainline models) and then "Bachmann Branchline", again mostly ex Mainline models, and earlier Bachmann models.

 

Many of the former Dapol models, now made by Hornby, were originally made by Mainline and Airfix (GMR).

Airfix, I think did not use a split-chassis.

 

Bachmann have been working through their range, updating the chassis to a more conventional DCC ready format...this is taking some time, and spare chassis seem not to be available from Bachmann to update older models.

 

Some parts sellers do sell chassis, often from models "broken" for spares....

 

[81F]

I don't think Hornby ever made split chassis locos.  Those Hornby and Triang models with pickups on one side only are live chassis models.

My Triang Rocket has but the problem with that is where to put the chip!

 

I've just finished fitting a chip to a Bachmann Mogul. Which also has asplit chassis and that was is a real chore, though not as bad as the mainline versions.

 

The worst part was that I had to file away a large chunk of the chssis castng in the smokebox to provide space for the chip. This is something of a slightlysoul destroying task so I spen about 10 minutes each evening over about four days. To add to the misery the wires on the hornby decoder were about 10mm too short to reach the motor (more soldering). Then as I was putting togeher the pston fell off the connecting rod (fortunately I had a spare set of wheels from a dud that I kept for spares.

 

The thing now runs quite well (touc wood) the only thing is that I've misplaced the tender!

 

Getting back tothe N2t I didn't know the mainline ne had a split chassis (as it was an ex Airfix GMR) and neither the 61XX prairie or 14XX autotank were.

 

[poliss]

Put the decoder over the worm gear 81, as seen here. 😆

http://www.rmweb.co.uk/community/index.php?/topic/34949-trianghornby-rocket/

[81F]

Put the decoder over the worm gear 81, as seen here. 😆

http://www.rmweb.co.uk/community/index.php?/topic/34949-trianghornby-rocket/

Thanks poliss looks frighteningly fiddly but I will probably give it a go if I can get the thing unning OK

[Southern1234]

You said "Please advise. I recently bought a nice little N2  Mainline loco and took it to my dealer for Hornby chip fitting. Nasty surprise  ☹️.  I was told it was a split-chassis model and thus very hard to convert to DCC. Therefore expensive (more than I paid for it )."

Your dealer was wrong ! The Mainline N2 was designed by Airfix GMR but Airfix went bust and the Palitoy Mainline organisation took the model into production. It has a conventional chassis and motor and a DCC decoder can be fitted by soldering the appropriate wires to the pickups and motor.

Hornby later took over production of the N2, made some good detail improvements and a different motor.

Don't believe everything your dealer tells you !

Ian

[Jimbo1707820979]

@ Southern 1234

A big thanks for this vital bit of information. I now feel better as I really like this loco and did not want to sell it on. Best regards.

[The son of Triangman]

As has been said the N2 has a conventional chassis design.  Ones to avoid are where the chassis is built using two slabs of metal in a vertical form held together with plastic spacers, washers, and screws. These are the infamous split chassis locos, some mainline locos and bachmann locos have this design. Some are easy to convert, others try the patient of a saint, some like the J39 require a little metal removing to fit the decoder into the loco body propetly as the split chassis fills the loco body. They can go back together easy or your may get one that resists, usually the insulating washers drop out during reassembly or one of the  square ended holding pins will drop out of it's hole during reassembly.  You are best making a jig to support the pins whilst putting the thing back together if you convert a split chassis loco. Split chassis locos are labour intensive so most dcc fitters either avoid them or charge accordingly.  Your N2 is a normal  loco and a very easy conversion

[Jimbo1707820979]

Thanks , SoT. The loco has now been DCC'd. Fitted with a TCS 1021 T1`decoder. It runs nicely on my Elite track but not with my Select controller, which is a bit of a pity. However, I was told the TCS is a higher Amperage than the Hornby 8249 so maybe this will give me better slow running etc ? I don't know what the advantages are so would welcome some advice and comments. 😆

Certainly, the TCS chip comes with a nicely detailed leaflet about the various configurations available, motor control -speed graph, momentum etc. Kind regards.

[Fishmanoz]

The higher current capability will not affect slow running in the slightest.  That will depend on speed curve settings which are the same on all decoders by default.  The only advantage of higher current is being able to handle a higher current motor.

 

Without looking up the specifics, you will likely get advantages by being able to adjust more CVs, the 8249 being very basic in this regard with very few CVs supported. 

[poliss]

The motor will only take the amps it needs. Older motors take more.

TCS have better slow speed control because you can adjust CV2 amongst other things.

[Jimbo1707820979]

Thankyou, Fish and poliss. That is reassuring.

For the benefit of members who need information on this decoder TCS say "For the complete list of available features of this decoder, print out ADDITIONAL PROGRAMMING GUIDE THAT CAN BE FOUND ON OUR WEBSITE in the literature section."

www.tcsdcc.com