Running Problems

[ScottK]

Hi,

Back in July, l posted an issue about running problems with a Hornby Dublo 2-6-4T conversion, from 3 rail to 2 rail. I eventually found someone locally who repaired it and for a while it was working fine but then started stopping suddenly when running forward or when switched to run backwards. On closer inspection the front and rear bogies appear to jump the track, causing the loco to stop. As an experiment, l removed both sets and run the loco on the main six wheels. It run forward and backwards without any problem and was quick. I also cleaned the front and rear bogie wheels and then refitted them. The loco ran okay  but you could tell it wasn't running freely. Could it be the bogie wheels aren't sized correctly in terms of the gauge size or perhaps not an exact fit? What l mean by that is, is that l found  a rear bogie on eBay for a WRENN 2-6-4T which looks exactly the same as fitted to my Hornby Dublo. Could that cause a problem if parts,have replaced but not an exact match or like-for-like? 

Any help or advice anyone can provide would be greatly appreciated as l just want to enjoy watching this old loco run smoothly.

[Il Grifone]

The Wrenn components will replace Dublo one without problem, but have been modified to take tension lock couplings. A Dublo type coupling was supplied but it is not 100% reliable. These can be recognised by having a section missing from the rear to enable a click-fit.

Are the bogies free to move? Do they still have the original shouldered pivot screws? And, as a long shot, are the wheels still the original undersized type roughly 10mm in diameter over tread. Fitting the correct to prototype 12mm diameter size will lead to jamming against the frames and consequent derailment. I assume the wheels turn freely and are the correct 14.2mm back to back.

Good luck, these things are usually good at both track holding and pulling.

[ScottK]

HI II Grifone,

Apologies for not getting back to you before now. I've been doing a research and learning in the meantime. I found relacement Wrenn fittings on ebay which would fit but befote purchasing them, l took a closer look at the original fiitings. The distance between inside of the wheel facings, back to back  is 14.5mm or as close as.The bogies run free and perhaps too freely.Watching the loco go round the track, the front pony does just about runs over the rails and then jumps out. The rear bogie starts by sitting on the rail but quickly jumps the track once the loco gets going, particularly when going over points. The pivot screws don't look like originals. After reviewing the pivot screws on the Hornby Dublo Service Sheet 7,  (pat no. 7737) and finding them on ebay (7737 # Hornby Dublo Front & Rear Frame Screw  K10A) they are completely different to what's fitted. The dilemma is whether to bite the bullet and buy the Wrenn  components and hope that resolves the issues or buy the pivot screws first, which might fix the poblem too. After what l've spent to fix the conversion from 3 to 2 rail, which was never done properly, l don't want to throw good money after bad. So, might go for the cheaper option first and purchase the replacement pivot screws. I'll  let you know how l get on. 

[ColinB]

It is amazing with these so called repairers. I recently fixed somebody's loco that had supposedly been repaired by a "qualified repairer", the person asked me to fix it in desperation. The thing I have noticed is that they seem obsessed with using epoxy resin for everything when with a bit of thought, you can come up with a decent engineering solution. When I converted my 3 rail to two rail loco, I used the equivalent Wrenn parts, the issue you get with front bogies and pony trucks is that the original Hornby Dublo ones were not designed with electrical isolation in mind, so quite often the new isulated wheels touch the frame and cause shorts. To be quite honest you are only going to lose postage and packing, so do each bit a bit at a time and then not only do you save money but you will find what is the part that is causing the issue. The biggest issues I had with the conversion was the pickups. I used the Wrenn ones, but it meant drilling and tapping holes to take the new Wrenn pickup plate and plastic retainer. The tender on the Duchess even with insulated wheels caused issues when going round bends so I eventually had to put a layer of insulated in.

[ScottK]

HI ColinB, 

 

Thanks for your post. Reading your comments, l will go with the more cost effective option first and buy the pivot scews to see if that reaolves the problem.  If not, l'll look to biuy the Wrenn fittings. Having had the motor fixed, l just want the loco to run as it should. All very frustrating but l'm sure l'll get there. Thanks again.