Why doesn't the pony truck touch the track.

[Chrissaf]

You wrote "What is the wire there for anyway........"

Modern Hornby Steam locos [particularly TTS ones or ones that are made TTS ready] standardise on placing the decoder AND the speaker in the tender. The motor and the main wheel pickups still being in the loco. Additional wheel pickups also make use of the tender wheels. Thus these locos require four wires between the loco and the tender.

To make having wires practicable, Hornby use a wired plug and socket arrangement to allow the wiring between Loco & Tender to be disconnectable.

Hornby X6113 [wired plug]

Hornby X9958 [chassis socket]

This overview block schematic shows the principle of the wiring between loco & tender.

So to answer your other part of your question. If you put the speaker in the tender, but leave the decoder and the motor in the loco. Then you only need two wires between the loco and the tender. But if you don't include some form of plug and socket arrangement, then that solution could be impracticable if you cannot then physically split the tender from the loco because the speaker wires are holding them together.

Most 'users' compromise by replacing the rather large Hornby speaker with a much smaller 'sugar cube' speaker that will physically fit in the loco along with the motor and the decoder. Thereby negating the need to fabricate a non-standard 'plug and socket' arrangement between loco & tender for the Hornby speaker.

When the model is just 'DCC Ready' and does not have any decoder fitted, then a 'blanking plate' is placed in the empty decoder socket to allow the wheel pickup wires to be passed through via the tender to the motor in the loco. Thus the loco will not function under DC control if the tender is disconnected from the loco.

Atom posted whilst I was busy preparing my reply.

[Going Spare]

Regarding the type of pony truck wheels:-

Since 2005, Hornby's main-range class A1/A3 locomotives (including Flying Scotsman) have used a fixed pony truck and have been supplied with two pony truck wheelsets, one with plain- and one with flanged-wheels. Hornby do not make the flanged-wheel wheelset available as a separate part but it may be possible to find one on the secondhand market as I suspect most locos would have been bought to run on a layout and are therefore being used with the plain-wheel wheelset. The flanged-wheel wheelset can only be used if you have extremely large radius curves and points (60"+)

As far as I can establish, the Railroad-range Flying Scotsman took the fixed pony truck from 2012. However, there was an earlier also loco-drive Railroad Flying Scotsman from 2007 which I believe still retained a pivoting pony truck. As a stand-alone model this had product number R2675 and it was also in set R1072 but these may not be DCC-ready. Because the main loco chassis block was altered to take either a rigid screw-on pony truck frame or for the frame to be an extension of the chassis block itself, it is most unlikely that retro-fitting a pivoting pony truck would be possible.

[JS84Z]

Thank you all for the great info! Much appreciated!

But I guess my question really is: if the Railroad FS bundled in the train set is the same as the one sold separately and they are both DCC ready, then why does one have a wire in-between and the other doesn't?

[96RAF]

The one with the interconnect wire twixt loco and tender has pickups in the tender and the one without does not.

[ColinB]

I generally convert all my locos that have a tender to have the four way lead, either by buying the later tender base, if the tender top fits or doing a filing job on the tender base so that the socket fits. I got so fed up with either shorting wires or breaking valve gear when I tried to squeeze the electronics into the loco. The only exceptions are the unrebuilt Battle of Britain and Merchant Navy classes where the bodies are so wide and the valve gear simple, that it makes the job a lot easier.

[JS84Z]

The one with the interconnect wire twixt loco and tender has pickups in the tender and the one without does not.

 

 

thnx! That clears up everything .

[JS84Z]

The rear wheels are flange-less wheels and are designed to ride high above the track rails. The wheel axle is rigid and has no pivot, therefore they cannot follow the line that the rails take. The wheels will by design overhang the rails on curves and swing out past the line of track and ride high above the rails when traversing track points. This is totally normal for this loco design.

 

 

For this particular unit I received from Amazon, the pony truck hangs in mid air even when the loco is sitting flat on a straight track, is that normal? I looked at several videos of railroad loco on youtube and non of them had the pony truck behave like that.

[96RAF]

Yes it must be held clear else as stated the wheels would foul the rails as the truck hung out on curves.

[ColinB]

I must admit I have never noticed on mine whether it clears the track or not, the dummy part tends to shroud it. The 4-6-2 locos where it is fitted would quite happily run around the track if you removed the front and back bogies. In fact I normally do this if I am trying to investigate why a loco derails.

[Chrissaf]

Your question relates to the Flying Scotsman locomotive, this has to be one of the most commonly and consistently manufactured locomotive models of all time. There are many different versions of this loco from different manufacturers. Therefore it is inevitable that some versions will have the rigid hanging pony truck and some will not.

[ColinB]

I have been doing a lot of work recently upgrading my tender driven A4s and A3s to loco driven. Every chassis I have bought has the rigid hanging pony truck, I got the impression that this has been standard on the A1, A3 and A4 chassis for a long time, even the Railroad versions.

[LY shunter]

I do not have Flying Scotsman but I do have a Clan 6mt with a fixed pony truck and flangeless wheels. These are a perfect fit on the track and rotate when the loco moves along. Perhaps your model has been fitted with wheels of the incorrect diameter.

I do not know which version of the model you have but I think service sheet 380 may be the correct one .

[JS84Z]

I do not know which version of the model you have but I think service sheet 380 may be the correct one .

 

 

This is the one I bought:

https://uk.hornby.com/products/flying-scotsman-train-set-r1255m

I also have the Merchant Navy (rebuilt) clan line centenary edition, its pony truck is flanged, pivots, and sits perfectly on the track.

[morairamike]

Both my A4s have flangless rear wheels that are clear if the track. That's how they arrived they aren't supposed to touch or they would cause derailments.