Model Railway Forum

Hi Everyone

Things have not all been running well, only a few days after fitting the valve gear onto the rear drive unit, I have had to temporarily retire my big boy from service because of a petty ridiculous way in which the intermediate gear next to where the 3rd driving axle receives its power to turn from the motor is suffering from either 1 ( possibly both ) of the following issues :

1 ) The gear axle is worn

2 ) The chassis block around the gear axle has worn.

I know it is most likely that the chassis block has worn but, is it actually possible for the gear axle to wrar down ?

The 2 drive chassis for the loco came from 8f locomotives that I purchased over the last 21 years and hardly ran because they were too light footed and couldn't haul a decent length freight or passenger service.

Last night, I did some investigation too see if I could find the cause of the problem because when I ran the loco in both directions, the wheels on the rear drive chassis would lock up.

I have checked the clearances on the valve gear and it is ok as it was adjusted for adequate clearances the night it was fitted.

Next I removed the base keeper plate with my home ade pickups and rested it + wiring to the side out of the way and using light finger pressure, moved the wheels back and for and could see the neighbouring gear moving away from the driving axle as if sideways in a slot.

Can I ask please if anybody has had this issue with an 8F chassis and if so, how did you fix it ?, I would be very interested in any suggestions / recommendations for ways to fix it short of possibly trying to purchase a loco drive 8F chassis block and transplanting all the parts over.

I must admit, it feels like a huge kick in the face waiting for ages to finally get the valve gear for both chassis, fitting them, testing the loco, making adjustments to various parts only for a gearing issue to result in 50% of the locos traction gone, infuriating or what.

Hi Everyone

Here is the latest on my big boy locomotive project.

Last night I decided to try and see if I could cure the problem with the rear chassis on the locomotive and stop the 3rd axle from wobbling.

I can definitively say, it looks like I have found the cure for 8F wheel wobble, a piece of copper tube with an inside diameter suitable to fit over the affected axle as shown in the picture below which I reduced to 80 % of full size just in case it was too big for the forum to allow size wise



The copper tube bearing is on the left side of the gear, I must admit it was a lot easier to do than I thought it would be. The main task I had to do was file the chassis block enough to allow the copper tube bearing to fit nicely without any wobble and I am more than pleased to say it works.

Some other projects that have been on my list recently include a dapol class 155 which initially had a rather noisy ringfield motor. As I had a spare hornby class 153 chassis and motor bogie, I have fitted the body from the powered coach onto this chassis which the motor at the inner end instead of the outer end of the coach, however, the motor bogie itself also had a minor modification made to it before it was fitted to the unit.

Essentially what I have done is to fit 4 wheels from the hornby ringfield motor bogie ( used in the hst, class 110, class 25 etc ) onto the class 153 motor bogie.

All 4 wheels are the insulated wheels with the gear moulding on the back which is removed for the purposes of this modification otherwise the wheels will cause the bogie to lock up. I can hear the dreaded arrrrrrgh from fellow members when I say that 2 of these 4 wheels have the further dreaded traction tyres to prevent the unit from spinning it's wheels on the track.

The only issue I ran into was that the pivoting pin for the 153 motor bogie broke off and went awol resulting in a piece of white 40 thou plasticard having to be used with a screw through the top to secure the motor bogie and prevent it dropping out, the only side effect being the slightly larger hornby wheels cause the powered coach to sit a little higher when the 2 coaches are coupled together, replacing the remaining wheels should help, just got my dapol class 150 to repower now as its motor is now sounding like the 155 did before the 153 motor bogie was fitted.

I will get a few pictures of the 155 later.

Hi Everyone

Here is the repowered Dspol Class 155