Hornby MGR and LNER CCT

[Ravenser]

On ‎22‎/‎06‎/‎2019 at 17:35, SweenyTod1 said:

I have three LNER CCTs Two are Hornby, the other Parkside. When I built the latter I compensated one axle, as I thought it would be required on code 100 track, but it didn't like the long insulfrog diamond crossing, derailing most of the time. No problem through any of the pointwork though, so eventually the axle was de-compensated. It still wobbles, but stays on the track. When the Hornby ones came out, I bought one (eventually another) and they also wobble over the crossings. I know code 100 track is not ideal for finer scale wheels, but the layout is old and not worth ripping up to start again. I have the opportunity to operate a code 75 layout and a Parkside version runs happily on that. Perhaps some kind of infill of the frogs to stop the wheels dropping into the "chasm" might be the way to improve things? More ballast weight too? Your thoughts for a happy compromise please.

 

Tod

 

Yes . You are describing the major visible symptom of points that are too coarse for the wheels . This has nothing to do with the rail height (code100) and everything to do with the gap being too big for the width of the wheel. That's a function of the checkrails being set too far out, in order to accommodate coarse wheelsets with narrow back to backs. The technical term for this is not "wobble" but "wheel drop at the crossing"

 

the invisible but more pernicious effect of coarse flangeways is that the check rail doesn't work . It's supposed to clout the back of the wheel just before the flange starts to wander into the gap at the crossing - this is to avoid derailments

 

Don't "infill" the crossing - a horrible Continental HO bodge. All that will do is make wheels run on their flanges , not their treads - not necessarily a good thing with locos

 

On the other hand you could "Shim" the checkrails - ie glue styrene microstrip inside the wing rail (the rail at the crossing/frog - the true check rail is on the other side) using solvent. Trim it back to rail height with a scalpel and you should have narrowed the gap by the thickness of the microstrip - making it easier for the wheel to bridge. This assumes , of course that you don't have old coarse wheels on the layout and can tighten up the tolerances

 

Wheel drop is always worst on large radius/shallow angle pointwork where the crossing gap is greatest

 

Ballast weight is irrelevant in this situation . It doesn't matter how heavy you make the vehicle - if it has to cross the Grand Canyon it will still fall in

Edited June 23, 2019 by Ravenser

[SweenyTod1]

Thanks for your input folks. I thought "wobble" was very descriptive of the action of the van, but of course I take your point (sorry!) that reducing the horizontal gap through the crossing "frogs/Vs" would prevent the wheels dropping. That is what I meant by "infill", but I didn't make that as clear as I should , apologies for that. Your remedy is what I shall do, assuming that my colleague with whom I share the layout agrees not to run his Wrenn/Hornby Dublo locos and stock!  I have some suitable microstrip that should do the job, but some diplomacy and negotiation needed first, me thinks.

The Parkside van, when I de-compensated it, was checked on glass, but perhaps I should check the Hornby ones, as I assumed they would be ok .At my age I should know better than assume, but they run happily everywhere else. So onwards and upwards with the joys of model railways with all its idiosyncracies that bedevil my (73 year old) grey cells. Perhaps I should be put out to grass, static, of course!!!!!

 

Tod