TTS 47 Stops on Old Hornby points

[martigues12001]

Hello all, I purchased the tts 47, but I have on my layout a concoction of new Hornby points and old Hornby points which do not have the metal guide blades fitted to them, only plastic guide blades across the centre of the point. When the 47 begins to cross the plastic guide blades, the loco stops, and "error" appears on the Hornby elite, the 47 cannot navigate any plastic guide bladed point, I have returned the loco to Hornby, they have had the loco for five weeks, and my during my first phone call to them, they had been unable to find a fault, I am waiting for a second phone call, on the 22nd, I wondered if anyone has any idea what the fault is on the forum ?,

thanks,

tony

[poliss]

It's almost certainly a short circuit as it goes over the points. There's not much else that would cause it to stop and an error message appear on the Elite.

Are the old and new points the same radii?

[martigues12001]

Hello again, I had worked out it was a short, I have about 100 loco's and the tts 47 is the only one that has this problem, and yes, the points are exactly the same points, except, I have metal guide blades and plastic guide blades, the plastic guide blade points are Austrian made, the metal guide blade points are China made , if that helps at all ? 

[poliss]

It could be that the back to back distance between the wheels is wrong, too wide. It should be 14.4mm +/- 0.05mm. You could get them to check that when they ring you.

[Chrissaf]

The Elite is showing the 'error' display because it has detected a short circuit. Hornby support will more than likely report 'no fault found' because the issue is more to do with your points and less so the loco. Chances are the 'back to back' distance (width between the inner flanges of the wheels) is incorrect. There are areas on the points where rails of opposing polarities are very close together and the loco wheel can bridge them to create a 'short circuit'. The 'short circuit' trips the Elite safety circuit resulting in the 'error' display. Old DC locos and controllers tend to be more tolerant of these very brief transient shorts, not so DCC.

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There are many reports of similar 'short circuit' on points issues on this forum with various suggestions on what to do about them. Try this one for example (see my post, 7th one down on the linked page). There are others. Search the forum for 'short circuit' to find them.

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EDIT: Must type faster....the other's got in ahead of me with similar comments.

[poliss]

14.4mm Chris, according to DOGA.

http://doubleogauge.com/standards/commercialwheels.htm

[Chrissaf]

14.4mm Chris, according to DOGA.

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Too quick off the mark poliss. Once I saw your first reply, I edited mine to remove any conflicting contradiction whilst my edit window was still open. Bowing to your superior knowledge.

[martigues12001]

hello again, thank you both for your information, I did not know of the wheels distance problem, but I can understand how a wheel could become a bridge to the electricity , on both sides of the point, thus creating s short, thank you again for the information ! 

[poliss]

I've typed it so many times Chris, that I know it by heart. Can never remember what the N scale distance should be even though that's the scale I model. Luckily I have a gauge so I don't need to remember. :-)