Hornby 0-6-0 Chassis Adjustment

[rpjallan]

Hi Everyone & Happy New Year.

I have a Hornby LMS Jinty 0-6-0 loco that someone gave me quite a few years ago (I believe it was 2nd hand) that is in great condition. It is the chassis with traction tyres on the middle axle unfortunately. I remember when I first got it, I tried running it & it made a loud screeching noise & because the traction tyres were a bit degraded, they fell off. I ended up just putting it away but a few years later, when getting some traction tyres for my Schools Class, I got some for the Jinty as well.

Anyway, I recently got it out & gave it a good clean & service & replaced the traction tyres. It runs well on my rolling road & small test layout. I have mentioned in a couple of other topics on here I am going to give making my own stay alives a go. I thought of using the Jinty as a test bed as only having pickups on 4 wheels would be ideal for this. Now this chassis has springs under the rear axle & it appears these are holding the middle axle almost 1mm above the rails. In the maintenance sheet it says this:

PLEASE NOTE

The 0-6-0 Locomotive chassis is designed to provide a strong hauling locomotive with good electrical pickup and low weight.

A balance has to be achieved between the strength of the coil springs holding the rear driving axle down and the body weights which compress the springs and keep the traction-tyred centre wheels in contact with the track. Therefore, the chassis cannot be performance tested without the body in place.

The spring pressure may be reduced by snipping off one coil from each spring. Pressure can be increased by inserting discs of paper or cardboard, 2mm. in diameter, into the spring location holes before refitting the springs.

Does anyone have any experience doing this? I guess it's just trial & error. Is it even critical? As long as all the wheels are running on the rails.

Any advice would be Greatly appreciated.

Richard

[P-Henny]

@rpjallan

......... I have mentioned in a couple of other topics on here I am going to give making my own stay alives a go. I thought of using the Jinty as a test bed as only having pickups on 4 wheels would be ideal for this..........

 

 

You haven't said whether your Jinty will be DCC converted, but be aware that 'stay alives' use polarity sensitive Electrolytic capacitors. Which means that they are designed to work with DCC Decoders. They are not compatible with Analogue DC locos that do not have a decoder fitted. This is because with Analogue DC locos, the voltage applied across a stay alive capacitor can be reversed. Place a reverse voltage across an Electrolytic capacitor and it will swell up and burst its seams.

I believe there is a 'workaround' for this, but I have no personal experience of it to comment upon whether it is without issue. In some online resources it is suggested that putting two Electrolytic capacitors in series but with their polarities opposing can allow the capacitors to be placed across a reversing voltage. That is to say connecting, for example, the two negatives together so that the connectivity path goes:

Left motor terminal to capacitor one positive then capacitor one negative to capacitor two negative then capacitor two positive to Right motor terminal.

If this does indeed work as other resources suggest it does, then the only issue I see is that the capacitors are not isolated from the track rails, thus the capacitors could discharge through any other device that is connected to the track external to the loco.

Personally, I would only ever attempt to fit a stay alive to a DCC decoder. Decoders have a 'bridge rectifier' to generate a constant polarity voltage to operate the decoder. The bridge rectifier output polarity is always the same regardless of the track voltage. The 'stay alive' is then connected across the output of the bridge.

[Rana Temporia]

You can now get some quite large (in electronic terms) non-polar electrolytic caps but since I stopped making guitar effects I haven’t kept up to date with developments in electronics, I don’t know if they would be large enough to use on a DC model to smooth out supply and deal with small interruptions. I would also be wary about the voltage rating due to effects from the motor, possibly going for something above 25v.

I do remember someone connecting two polar caps together as suggested to make a mega-bass boosting circuit but I never tried it.

[threelink]

I am totally ignorant about DCC but do have a Jinty such as you describe, with the same problem (centre wheelset held too high). I cured it by adding weight - far simpler than messing about with spring lengths. Good luck in achieving your aims.

[rpjallan]

Thanks @threelink. That is a good idea. I have some lead that I can use.

@P-Henny & @Rana Temporia, my question was not about DCC (if it was I would have put this under the appropriate forum). It was about adjusting the suspension springs on the rear axle. Did you read anything after the 1st paragraph?

I have been using DCC for over 15 years. This loco has had all the wiring removed & a decoder will be hard wired (it previously had one of the early hornby decoders fitted, R8215 I think which is of no use now). I intend to test my stay alives with a few different decoders in this loco also...

[P-Henny]

@P-Henny & @Rana Temporia, my question was not about DCC (if it was I would have put this under the appropriate forum)...........Did you read anything after the 1st paragraph?

 

 

Yes, I did read the WHOLE post closely before replying. I base my replies on what is written in the post. I don't have a crystal ball to know what you haven't written in it.

Which is precisely why I gave the reply I did. Everything in the post inferred that the loco would be DC i.e. in the Analogue forum and no mention that any Decoder would be fitted. I was totally aware that the focus in the post related to a physical wheel issue. It was you who mentioned the 'stay alive'. I was just addressing that particular 'stay alive' element of your posted text. I wrote my reply purely as an advisory "be aware" reply, not knowing anything about your DCC experience as there was nothing in the post to say any difference.

Looking at Rana's reply, it would appear that he too was following up on the basis (presumption) that you were intending to fit a 'stay alive' to a DC loco.

Can I humbly suggest that if forum members provide additional information that is of no interest to you, that you just ignore it and not criticise them. The additional information, although not of interest to you, may be of interest to others who might be searching for, in this instance, 'DC Loco Stay Alive' info.

[rpjallan]

I would simply like an answer to my question if anyone has experience doing that. Not irrelevant stuff clogging up the topic.

Maybe I need to give less info next time...

[Going Spare]

Is the lifting of the centre wheelset such that the tyres do not touch the rail surface? I have never found it necessary to reduce the length of the springs: if anything, they tend to compress. The chassis block recesses in which the springs sit can collect dirt; have you checked they are clear? As you have not owned the loco from new, are the correct springs fitted? I forget their true application but there were similar looking but stronger springs that fitted.

[rpjallan]

Thanks for your reply.

Yes, the centre wheel set is about 1mm above the rails & the traction tyres are brand new. I completely stripped the chassis down & cleaned it, including the holes where the springs locate, and even blew them out with compressed air. When I got the loco it looked like it had never been used so I doubt that it had ever been apart, let alone the springs replaced.