Platform loop

[TheGreenGuit]

Could someone advise me what combination of track is needed for the entrance/exit of a platform loop (Hornby platform)?

[Clement Matchett]

As others have pointed out, notably Charlie Bishop at Chadwick, there is a problem with platform loops with the TT120 locos released so far by `Hornby, in that none of them have front couplings. So the Heritage practice of decoupling the loco from the train at a terminus and running it through a loop and attaching it to the rear of the train, to enable it to take it back to its starting point tender-first, cannot work.

But, in a long-winded attempt to answer your question, you need two points of opposite hands, two 6th radius curves, and enough straights both to enable the loco to be driven forward across the terminus point and allow it to clear.

It is simpler now to describe the process. The point is then changed, the loco placed in reverse, and driven along the train, backwards until it rejoins the main incoming line, the point behind the last carriage having been changed to allow that.

Then, in Hornby 120, you need The Hand of God!

Hopefully, He is not too busy.

[Clement Matchett]

..,and as an addendum, you need much the same if, rather than arriving at a terminus, your train is just clearing the main line to a stop at a platform, the track is much the same. There is no purpose in having a platform loop unless that allows a later train to take the main, avoidance line.

[Fishmanoz]

My interpretation of the question is a little different - to have the loop wide enough to clear around the platform, you use, point, extended half straight then R6 curve back to parallel.

That is the sole purpose of that track piece.

[Rallymatt]

👍 Fishy, I didn’t know the actual pieces required in Hornby Geometry,

[Fishmanoz]

That’s what’s been said previously.

What I’m not sure about is the straight sections needed before you go back at the other end of the station because the 92mm extended straight at 15 degrees after the point doesn’t seem to be any set track straight length. Might be a half straight, will check some time. I use Tillig flex in Anyrail to play around with stuff like this.

Reason I don’t think it is a half straight is I know that 170.76mm at 15 degrees is 166mm horizontal and, together with the point and R6 is 83mm vertical.

[Fishmanoz]

Confirming that if you use the 92mm extended half straight between a point and R6 curve back to parallel, you end up with a gap between track centres of of 67mm which I’m assuming is sufficient to fit a platform.

But then, if you use the same arrangement to loop around the other end of the platform using standard straights between the R6s, you end up with a gap of standard straights plus 177m on the through line between the points, or 11mm more than a standard straight.

So can’t see how you can do this using only set track.

[TheGreenGuit]

Thanks Fishmanoz. That is what I meant. I just want a train to be able to use the other side of the platform coming off a straight, waiting and then be able to rejoin at the other end, whilst creating the correct gap to accommodate the platform. However it looks like the solution is not straightforward.

[Too Tall]

I have the answer, once the post has been approved sunglasses

Leaves you with an 8-9mm gap between platform edge and sleeper edge both sides.

The other option is to use flex track if you want a different gap, both Tillig and Peco Flex should connect to Hornby OK.

[Too Tall]

Right click pic and select open image in new tab to see full size.

There is the smallest of gaps, easily within the bounds of adjustability.

[Silver Fox 17]

I don't know why no one has mentioned the easy and obvious solution, just cut a piece of Hornby track to suit.

I have cut a few, straights and curves, to fit in with my plans.

I do this as I don't like the Peco track (my choice I know many do).

[Dave the Busker]

Using a point and 6th then two 6th to simulate a Y point:

[Rallymatt]

Silver Fox, absolutely, I did mention cutting set track on another thread to accommodate quirks. Did it in the early days to eliminate need for lots of little bits of track and wobbly fishplates (days of carpet based running) 😁

[96RAF]

Could someone advise me what combination of track is needed for the entrance/exit of a platform loop (Hornby platform)?

 

 

The 8037 is used to expand the loop to go round a Hornby platform.

[Dave the Busker]

96RAF, I only have a track planner to go on, so the exact geometry on it might not be correct and it might all join up fine, but when I've laid it out with the extended straight I always get a gap when I try to connect the loop back to the main line. Is there anything we should be doing to prevent this?

[96RAF]

No idea Dave, my solution was only to get the width to accommodate the platform. I presume you may need to insert flexi in lieu of some of the 166mm long bits.

Does your track planner have the option to adjust connection tolerances, like SCARM can.

[Dave the Busker]

Aye, it's set with the tolerances quite high. Looks like a job for flex track / cutting straights to size. (Unless as I say the software has the geometry out slightly, don't have any extended track here to test with)

[Robc058]

I created a passing loop with only standard straight track + needed 6th radius *2 and turnouts *2.

But I have since changed the design.

[Clement Matchett]

ad Robc058

So did I. And I am sticking with it for the moment.

I don’t like the Hornby platforms..they are too much of a toy for me.

But having received some laser-burnt MDF ones, I think they are too high.

I have been on hundreds of British trains but have never stepped down into a carriage from the platform.

May have to resuscitate the belt sander.

[D9020 Nimbus]

There is a bigger range of track pieces in the Tillig Modellgleis range than just the Hornby full/half/quarter straight, though nothing the length of the "extended short straight". In particular there are 36.5mm and 43mm pieces; there's also a variable length "module linking track".

They connect fine to Hornby track and make some combinations possible that otherwise wouldn't be.

[Old Kent Biker]

@cm said "But having received some laser-burnt MDF ones, I think they are too high."

Are you mounting the track on cork underlay? This may take up the difference in platform height.

[Clement Matchett]

Ad Old Kent Biker

No!

My baseboard is quite small - 1687 x 809mm, sitting in an alcove, and I use 28mm Mdf.

The trains run reasonably quietly, but putting the layout in an alcove with plastered walls produces quit a bit of reflected noise. But it is what it is.

The height issue is not extreme…I will probably sand the platforms off.