a marche!

A double loop round the games room, 27' x 17', double track most of the way with a couple of quadrupled sections for passing and holding
trains. The 8F can /just/ climb the steepest incline, 1:40, pulling a train of about 400 2" oval brads equally distributed among 24 trucks, and the points are all flat enough that a well assembled train will run over them without any derailments. Six control sockets for the DCC handsets, a couple more needed, and some of the sidings operational as well, including the turntable.
Importantly, the lifting bridge and the trundleduct work flawlessly, and the points on the trundleduct (which were a compromise forced by circumstance) actually do work.
The execrable tender-drive Hornby Flying Scotsman also runs round without derailing, but can't take much in the way of switching (this is normal for the model). N2 runs perfectly and so does the DMU so I am pretty confident that the trackwork is all flat, the transitions smooth enough and the power supplied without excessive volt drop. It's taken at least a year and a half since I started in earnest, the points are not yet powered and there is no scenic down yet, but the loop is closed and....
WE CAN PLAY TRAINS!
Which is all we care about!
So I have two happy boys and a moderately happy me. Time for a celebratory pint, I think.
http://www.chapmancentral.co.uk/wiki/Railway will have some new pics tomorrow, I hope, after the mother of all tidy-ups.
Guy
--
http://www.chapmancentral.co.uk

"To every complex problem there is a solution which is
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Now dont take exception to this ....but when you say "tender-drive Hornby Flying Scotsman also runs round without derailing, but can't take much in the way of switching (this is normal for the model). " its very easy to fall into a trap of blqaming older models. I did it with some coaches that have older style wheels. They failed a few new points with regular derailing. Immediately blamed the wheels. Then thought pity really cos they look nice coaches so decided to check the B2B. Now I regularly clean track and loco wheels else locos wont run but had never done coach or wagon wheels. There were ridges of black muck on some wheels. Have learnt lesson - 2 really, donr assume cos older and clean all wheels.
So if you want it running all over - and if your lads are as cussed as mine then that would be the one desperately needed - suggest you investigate why it dont run.
Cheers, Simon
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The problem with the Hornby A3 is that the tender runs crabwise under load, due to the use of traction tyres I guess. I do clean the wheels and everything else - in fact I have replaced most of the truck and rolling stock wheels with current-generation Hornby metal wheels, which run much better than the old plastic ones.
Guy
--
http://www.chapmancentral.co.uk

"To every complex problem there is a solution which is
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Would be interesting to hear other opinions, but for crabwise with load, would look at couplings. Either off-centre or bent hooks.
Cheers, Simon
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 01/01/2009 11:40, simon said,

I must admit that my first thought was that it's because the traction tyres are only on one side of the tender.
--
Paul Boyd
http://www.paul-boyd.co.uk /
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

The problem causing that behaviour is that all the axles of the tender have uncontrolled sideplay. You need some plasticard washers on two axles to calm it down. Use known thicknesses of offcut plasticard as feeler gauges to messure the free play. You want a washer each side of the chassis block on the axles, thinner than half the free play. - Drill an axle diameter hole in the plasticard. - use an office paper punch to cut the outside of the washer. (underneath the punch there is a hole to let the punched bit out, you can center the drilled hole visually)- - do twice as many as you need and pick the best ones. - cut out a 90 degree segment of the washer. (the narrowest side) - rub both sides of the washer on a fine flat file to get rid of the burrs. - the three-quarter washer can now be slid between wheel and chassis and "snapped" over the axle. - do that behind four wheels and your A4 tender should run straight.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Will that stop it wobbling too?
--
Martin S.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
MartinS wrote: [snip instructions on fitting washers to Hornby powered tenders]

The wobbling is caused by the traction tires. These are not high-precision devices, nor do they fit perfectly, thus a wheel with traction tires is not round. And so the tender wanders down the track like a drunken duck.
You can permanently replace traction tires by filling in the grooves in the wheel treads with epoxy glue. Remove the wheelsets, thoroughly clean them, squish the epoxy into the grooves, and smooth as well as possible. After the glue has hardened, reinstall the wheels, apply power, and file the epoxy smooth. Gently - you want to take off less than a thou of the metal tread.
I've done this, it works well enough, but it's best IMO to use all-metal wheel, no traction tires. Load up the tender with as much weight as will fit into its nooks and crannies. You will have less traction, but unless you run 12-13 coach rakes or longer, you won't notice. Also, the coaches should be as free-running as possible. They should start rolling without a push on a 1:100 gradient or less, and should keep rolling after a push on a 1:200 gradient or less.
HTH
--
Wolf Kirchmeir

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I keep saying this: throw away the poor quality traction tyres and replace them with Maerklin or Roco traction tyres! They are constant width, constant thickness, oil resistant and don't shed. They also increase grip on the rails. When you first put them on they can bunch up a fraction at one point - I hook a fine jewellers screwdriver between the wheel and tyre and run it right around the wheel - otherwise they will settle after a little running. I certainly have tender drives that are too small to accept enough weight to give acceptable running on metal wheels, for example the Roco German BR 58 (2-10-0),. With all metal wheels and no spaces left for more weight it would barely move itself around my layout (1:40max gradients). With one axle tyred, two metal it would haul a reasonable train but was prone to slipping with horrible sound effects. Two axles tyred and it pulls well.
Regards, Greg.P.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Greg.Procter" wrote

But when you stretch them over the wheel flange & push them into the grooves in the appropriate wheels they lose their uniforminty - maybe not as much as the crap offerings of Hornby, Lima and others from the past - but they are no-longer round.
Whatever make, traction tyres are a nonsense, if only because they restrict the free collection of electrical current from the track. They have no place on any model railway - period.
John.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 8 Jan 2009 08:49:28 -0000, "John Turner"

Somebody somewhere will now start scratch building a Michelin railcar as featured on this page http://www.railcar.co.uk/railcar50/display/02.htm just to be awkward.
G.Harman
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Maerklin/Trix did one a couple of decades back! It has all ten wheels in metal with plastic wheel/tyre discs snapped on the outside. And can motor, decent gears etc etc. Works well in two rail form.
Greg.P.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Fri, 09 Jan 2009 09:36:36 +1300, "Greg.Procter"

Blast ,that is the sort of quirky model I like even though there is no reason to have one. Off to Auction sites we go,see it was done under the Hamo label as well.
G.harman
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Sorry, yes it was under the Hamo label, not the Trix label. (Trix bought by Ma 1997)
My guess though, is that it was done outside the Ma factory. (Can motor, worm gears ...) There were several French liveries (Nord, Est ...) then a Michelin (demonstrator?) then about a year or so later numerous odd and possibly questionable liveries. My one is as the Michelin demonstrator (red) but no major markings beyond railway data.
Greg.P.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Hi John,
I'd really like to see the repair where you have to stretch the tyre over the flange! ;-) Yes, I agree that putting the tyre on the wheel stretches it out of round, but we do the same thing with car tyres and there are few complaints about out of round wheels there. If one bares in mind the problem and fits the better quality tyres carefully there is no discernable problem. I've replaced numerous British/Italian/Chinese tyres with Ma or Roco and have had a lot of positive comment back from the owners. Of course, one could toss the nasty mechanisims out and replace them with can motors and quality gearboxes, but the conversion would cost more than the original model.
As to traction tyres being a nonsense, I'm inclined to agree, but small steam locos with small tenders are a design problem for those of us who like round boilers and for manufacturers using plastic as their main material and who try to minimise weight. For my own scratch-built locos I've gone to making near solid metal locos with a gearbox on one axle and a motor/flywheel in the tender with a cardan shaft between. Of course, when one is talking 2-4-0s with 2 or 3 axle tenders operating at up to about 40 scale Kmhr one needs every pick-up point one can get. A friend banned one of my locos from his layout as he thought it would be too heavy and damage his plastic kit bridges! =8^)
Greg.P.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Greg.Procter" wrote

Yes, that was a thoughtless comment & worthy of your smiley.
John.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Remove the wheels and just use the plastic washers as replacements - they will almost certainly be more concentric ;-)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.