[cookiechem]

Hi All,

A few weeks ago this forum was very helpful with the baseboard and planning phase of the layout I was building for my son. Things have moved on and the layout is complete, though it is not without a couple of teething problems. Small locomotives (shunters and the like) have a habit of sticking on the frogs of points. The points are Hornby and have been made live with the little staple thingies. The sticking doesn't happen every time (around 75%) and only happens when the point is switched to the turn-out.

There are also other occasional short-circuits where the a train (again only the little ones) will die on a seemingly random piece of track. After a nudge the train will take off again and probably never stop at that section again.

Any advice on these short circuit problems is much appreciated.

The layout is controlled by DCC.

Cheers,

Greig

 

[Robert Stokes]

I don't think that these are short circuit problems as that would probably make the controller shut down. I think that they are loss of current problems. The fact that it happens with short engines is because they have few wheels picking up current. One wheel may not be making contact at all because the rail is not perfectly flat so it is riding high. Another reason is perhaps dirty wheels or dirty track.

I don't think that the little clips turn Hornby points into live frogs, they just let current go both ways. This means that on the dead part of the frog the short engine has even less chance of proper contact.

I suggest that you investigate dirty wheels and track first. I don't think that there is anything you can do about the frog on points. I hope that you get it working correctly though.

 

[alastairq]

I have had this sort of problem with 'small' locos since the year DOT.....and haven't even investigated DCC yet.

As Robert says, the issue is a 'loss of contact'

Hornby points still have a large, plastic [ie insulated] crossing section.

With smaller locos, there is a tendency for the wheel negotiating the crossing [what you know of as the frog] to 'dip' into the void between the supporting rails.

[ideally, the 'tread' of the wheel...the flat[ish] bit.....should be continuously supported through the crossing...ie the 'gap' should be narrow enough that before one bit of rail 'let'sgo', the other bit has taken over.]

This doesn't happen with set-track points....and some that ought to be better too....due to the 'dimensions' of wheels, checkrails, etc.

so..the loco dips......which raises the opposing wheel clear of its rail too....hence, loss of contact.....hence abrupt halt.

This is the main issue which resulted in the finer 'scale' brigade resorting to the likes of 'suspension' and 'equalisation'.....ideally a ''3-point' suspension system should be encouraged, allowing some vertical [and rocking] movement of one of the loco's axles.

to overcome?

Apart from ripping out all the Hornby points [or Peco insulfrogs, or setack].....and re-designing the whole layout to accomodate something like, Peco live frog points.....[which bring their own problems with DCC I understand].....then one is left with 'home fettling'.

Firstly, get hold of a LARGE FLAT FILE......the sort used for Formica are good......[flat mill file, for those in the know]....and CAREFULLY [turn off the current first] pass it over the top of each point.

This hopefully will take off any ''high spots'' on the plastic crossing area.

If one is running stock with similar sizes of wheel...ie flange depth, then another trick is to cut out a shim of plastic card of a few thous thickness [I have used 5 thou]...and 'glue' into the 'well' of the plastic [frog] area, in front of the crossing vee.....this may help 'support' the wheels as the cross the open area....but wont work unless ALL flanges are the same....this will reduce the 'dip'.

another trick is to glue thin pieces of plastic card into the [frog] area....inside of each wing rail...ie inside the two legs of the Y bit.

a swiss file [why not a french one?] passed through the flangeways will ensure nothng protrudes...

these shims will hopefully 'pick up' the wheel treads 'earlier' in their passage through the [frog] area...thus supporting them, reducing 'dip' again.

Of course, check each loco's pickups....for tension or pressure especially.

what you are looking for, is any break in contact of the pickups....WHEN THE DRIVERS ARE PUSHED TO ONE SIDE OR THE OTHER.

which will happen [sideplay] when the loco enters the curved portion.

THE BEST HORNBY SHUNTING LOCO I HAVE COME ACROSS, IS THE J94 0-6-0 TANK....[FOR THE PRICE].
apart from one, none of ours...we have quite a few.....fail on Peco setrack turnouts.....the one mentioned had non-concentric wheels.....and is being re-wheeled..and possibly re-gauged...with Gibson wheels of the CORRECT pattern......and has been for the past 6 years or so......lost my box of round tuitts.

 

[alastairq]

thank goodnes for the 'edit' feature......I spotted some humumgous speeling errors in the above...hope no-one read it beforehand....

 

[cookiechem]

Thank you so much for the replies. Imperfect contact with the track is the probable cause of the random stops. Looking along the track I can see a few points where it dips slightly, due entirely to my tacking it down too hard into the Gaugemaster ballast/underway (expensive but looks great). This should be easy enough to tweak.

The problem with the points looks like it may be harder to solve, if it can be solved. I will try gently filing the plastic frog to remove any "over-height". Other than that, the locos may just need the occasional nudge to keep them moving when shunting.

It is frustrating that such a mass market product as a Hornby train set has a few endemic problems that make its operation more fraught than it ought to be.

 

[alastairq]

by using a 'mill file' of large size [re my previous post] the idea is, the opposing railheads provide a guide to levelling....make sre the file passes over all railheads in the vicinity of the [frog].

I'd take a gander at the loco pickups firstly....as I mentioned, check to see of the pickups arer still ''in contact'' with the wheels, when the axles are pushed fully sideways?

maybe worth passing a tissue between the contacts and the wheels?

This 'frusration' has been known to 'put off' young folk from model railways for many years...hence my advice regarding the TYPE of loco used......which in itself isn't 'new'...I got it from somewhere many years ago.......probably CJ Freezer again...who used to advise buying Goods trainsets because they had greater 'play' value.....and avoid 4 wheel engines for starters.

[another of his gems concerned'being selective about the stock bought for the youngster'......making sure it was all 'in keeping' with the [limited?] size of the layout. This was a problem I tried to address with my young son's layout.....due to tight curves, limited platform length, etc, I tried to get him only interested in 'short' coaches.....this helps with the 'quantity' issue, as well as aiding in keeping the INSIDE platforms closer to the tracks...without that huge gap necessary to accomodate the likes of Bachmann Mk 1's on tight corners.....needless to say, once he SAW the bachmann coaches, there was no turning back, and I had to trim the platforms as a result.]

 

[Basil]

QUOTE (alastairq @ 1 Jun 2008, 14:39) <{POST_SNAPBACK}>thank goodnes for the 'edit' feature......I spotted some humumgous speeling errors in the above...hope no-one read it beforehand....

Well done editor

but what graeat advice.

As a restarted newbie, this advice is great.

Thanks

 

[34C]

QUOTE (alastairq @ 1 Jun 2008, 15:35) <{POST_SNAPBACK}>THE BEST HORNBY SHUNTING LOCO I HAVE COME ACROSS, IS THE J94 0-6-0 TANK....[FOR THE PRICE].
No traction tyres, and a sprung centre axle, so not a completely rigid chassis. That gives the potential for collection through 5 wheels at any one time if the individual wheel back pick ups all maintain contact whatever the lateral position of the wheels. In my experience it has been a rare newly purchased RTR loco that doesn't need at least one pick up wiper adjusted to ensure this, though I am honour bound to also report a run of seven out of seven perfectly set up new purchases in the form of 3 Hornby Brits and 4 Bachmann 9F's.

The Bachmann Jinty and 57XX (and a number of others) have a spring plunger on a driven axle which means that they share the advantage of the J94. Except that Bachmann pretty much constrain the sprung axle travel below the line of the rigid axle wheel surfaces with the keeper plate. Whip off the keeper plate, and cut notches in the sides and the centre rib to allow the axle and plunger a little more downward travel (not too much, you don't want the axle shorting the pick up strips) to obtain this advantage.