Jump to content
 

Finally Hornby Pullman Coupling Fault Corrected.


Recommended Posts

I know from experience and other's that the Hornby Pullmans can cause massive difficulties regarding derailing. So-much-so I know some have given up on them completely.

IF you have never had a problem, move on, nothing for you here. I was as pleased as punch to get the top-of-the-range Hornby lit Pullmans. A set of three. I added the NC bar and the Observation Car. The latter, and the Bar having the later deep cupped bogies to facilitate close coupling but still permit usage on second radius curves. A modification to cure the earlier coupling problem Hornby left us with on thousands of earlier 'fully-detailed' Pullmans.

Initially I felt the answer was simply to get some lubrication into the sliding area of the coupling. More luck than judgement, I made a few rotations so thought I'd cured the derailing. NOT SO. Two choices jumped out at me. 1. Sell em and let someone else have the problem: or 2. See if I could TRULY get them running properly. I decided on 2. My head itched badly so with a good ol scratch and a mod that has 100% cured the problem I'd like to share it. I KNOW many have given up on the early 'slide and hide' type couplings. So what causes the derailing?

Simply put: the coupling slides, as it is designed to do so, but can get stuck. The slide facility goes well past the edge of the curve. A quick flick and it gets wedged between bogie and coach body. This equals a quick and nasty derail as the bogie has no way of righting itself coming out of a curve. You can actually look down and see the coupling stuck to the left or right. Generally though it is enough of a problem to literally throw the coach down sideways, and pull out the coupling from the securing screw. The problem is the over-shoot of the sliding coupling. It actually needs not go past the edge where the curve meets flat. On the later coaches a much deeper half circle is there with limited travel of the coupling. Instant cure.

I wondered if using my Dremel to smooth the hard edge would cure it. It lessened the problem to be fair but it did not eliminate it. In the end I felt the only option worth trying was restrict the amount of travel the coupling makes across the bogie. I made some small plastic blocks from an old OO fence. I glued them in place as can be seen. I've painted them black but for this have left them cream colour so you can see where they are. They really are tiny blocks. I had my doubts: I felt no matter what I tried these Pullmans had been sent from hell to try my patience. SOOOOOOO. This afternoon between 14.30 and 16.25 I had the Deltic DP1 Sound off, tugging five coaches. Three old style lit Pullmans, the Bar and the Obs Car. That is on an eighty foot loop through second radius curves. The blocks stop the coupling leaving the half circle in the bogie, which is actually the maximum the bogie will physically swivel to. the coupling now rolls within the curved area of the bogie and will not travel past the edge. I used small plastic blocks which are glued in place. I could not see any other way of limiting coupling travel other than a full strip down. This way all you need to do is unscrew the coupling, fit the blocks, and refit said coupling. For almost two hours at varying speeds, and for the very first time, the Pullmans did not derail. In the accompanying images you can see where arrowed what happens to the coupling and where it can get stuck.

a.jpg

b.jpg

c.jpg

d.jpg

e.jpg

  • Like 4
  • Informative/Useful 5
  • Craftsmanship/clever 4
Link to post
Share on other sites

I thought I'd update. My Pullman rake including the Obs car have completed a couple of hundred rotations since I first fitted my little mods. The mods are still all attached which is good. This reduction in travel has really worked well. At best I could if I was lucky get two journeys. Now I can run the Pullmans tugged by the Deltic, the Class 40 or the Lord Nelson for as long as I like. Tried really difficult journey plans and thus far perfection. And to think I was on the cusp of calling it a day with Hornby Pullmans lol

The latter however does struggle a tad purely because of the weight. I stripped all the Pullmans and fitted filing weights as I thought that was the issue :) Maybe I should fit traction tyres to the LN :) 

Edited by Jerryatric
I forgot a bit
  • Like 4
Link to post
Share on other sites

  • 2 months later...

This is a very interesting post.

 

I solved mine by making replacement connectors between the coaches out of 0.5mm blackened wire, so that one coach piggy backs on the next. The coupling itself was dumped, and the wire attached to the sliding mechanism using the screw hole. This is fine if you run fixed rakes.

 

More generally I think you have touched upon a potential downside with all these coupling systems, applying to other coaches as well, which is that the mechanism can serve to lock the free movement of the bogies, and even if it doesn't derail it can cause a lot of drag until eventually the bogie straightens up. This was so on a curve with a change of gradient and I noticed it with some Hornby Maunsells, otherwise brilliant models. Your remedy may provide an answer.

 

Thanks for posting.

 

John.

Edited by John Tomlinson
P.S. To be fair to Hornby, I had replaced their mechanism on the Maunsells with those from Bachmann Mk1's and Kadees, as I don't like my couplings to be below the line of the buffers - look at the original and you'll see what I mean.
Link to post
Share on other sites

  • 6 months later...
  • RMweb Gold

It seems to me that it's the little nib that slides above the curvy retainer that causes the problem. I assume this nib if they to stop the coupling dropping down. Any reason why I can just cut the nib off? Do the couplings then droop?

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...