Steam Loco's - minimum radius curves

Post your design ideas for any layout that you are planning to build in the future. Keep members up-to-date with your designs and future plans for your layout.
User avatar
GordonBigBoy
Posts: 73
Joined: Fri Jul 27, 2012 7:11 am

Steam Loco's - minimum radius curves

Postby GordonBigBoy » Sat Aug 18, 2012 4:08 am

Hi, I don't have enough room for a turntable so to overcome this I am planning a DCC reverse loop (R8236) on a lower split level on my DCC layout so that I can turnaround my steam loco's and get them facing the right way at the terminus, ready for departure. I would like to do this using 2nd radius curves. No carriages or other rolling stock would need to use this loop, just the steam loco's. The smaller branch-line loco's and shunters I imagine will not an issue.

The larger of my steam loco's will be (for example):

4472 Flying Scotsman
46241 City of Edinburgh Princess Coronation Class 4-6-2
Falcon Class A4 4-6-2
BR 2-10-0 Britannia Class 9F Evening Star
Black 5

I know 2nd radius generally is to be avoided, but in the case of a very slow running loop as described above can I have some views or comment on if it is feasible to run the big loco's?

Thanks

Ian
Gordon - A Really Big Engine

User avatar
Roger (RJ)
Posts: 1455
Joined: Tue May 29, 2007 2:59 pm
Location: Nottingham, UK.

Re: Steam Loco's - minimum radius curves

Postby Roger (RJ) » Sat Aug 18, 2012 7:54 am

I don't think you'll have any trouble with second radius.
My main running loop is 2nd radius and I don't have any problems running my Scotsman, Pendolino. railroad 9F or anything else. I can even squeeze my Pendolino round first radius if I'm really careful. The only problem I have is with crossovers using standard Hornby points. which have to be negotiated at low speed.

kristopher1805
Posts: 23
Joined: Wed Mar 28, 2012 3:22 pm

Re: Steam Loco's - minimum radius curves

Postby kristopher1805 » Sat Aug 18, 2012 8:29 am

Generally speaking should be OK, Hornby railroad locos such as the 9F eats R1 curves for breakfast but the Bachmann version may dislike them although they will pass through the standard ST 240/1 points which are nominally R2 as well.

User avatar
thebritfarmer
Posts: 1490
Joined: Tue Jun 14, 2011 11:46 pm
Location: Windsor, Ontario
Contact:

Re: Steam Loco's - minimum radius curves

Postby thebritfarmer » Sat Aug 18, 2012 2:57 pm

Would a reverse loop not take up as much space as a turntable though?
All Aboooooard !!

b308
Posts: 5006
Joined: Sat Apr 15, 2006 5:48 pm
Location: North Worcs

Re: Steam Loco's - minimum radius curves

Postby b308 » Sat Aug 18, 2012 8:35 pm

More I'd have thought! As long as it's out of sight then it doesn't matter, but if it's in view then large tender locos like them will look a bit daft as they always do when negotiating curves the prototype could only dream of!

User avatar
GordonBigBoy
Posts: 73
Joined: Fri Jul 27, 2012 7:11 am

Re: Steam Loco's - minimum radius curves

Postby GordonBigBoy » Sun Aug 19, 2012 3:34 am

Thanks for the replies guy - really helpful - I can now go ahead and purchase the 2nd radius track. Just to clarify for Farmer, I don't have room for the run-offs or sheds from a TT so I plan to have the reverse loop underground so to speak underneath and adjacent too the Penzance Terminus. I have not got a drawing yet but below is the v1 layout to give you an idea.

The information I have says 2nd radius (438mm) will fit a 2ft deep board - if necessary I can extend the depth of the layout by another foot in Penzance to allow optimum fit. The wall which Penzance will fit against is going to be @ 16 feet so a nice long run up to the Bradbrook corner. I am planning to station my Steam Loco's in Penzance (I will expand the sidings) and the Diesels and High Speed Stuff I will station in Bradbrook. I have to figure out how to connect the two layouts together without another reverse loop - still planning. Well it is v1 of the plan anyway....lol. Wish me luck.

Gordon BB Layout v1 railway train track DCC v1.jpg
Gordon BB Layout v1 railway train track DCC v1.jpg (119.96 KiB) Viewed 4300 times
Gordon - A Really Big Engine

User avatar
Roger (RJ)
Posts: 1455
Joined: Tue May 29, 2007 2:59 pm
Location: Nottingham, UK.

Re: Steam Loco's - minimum radius curves

Postby Roger (RJ) » Sun Aug 19, 2012 8:26 am

You can't fit a second radius oval on a 2ft wide board (2 x 438mm = 876mm, which is 34.49 inches to the centres of the track). The very minimum width would be about 36 inches and preferably a bit more.

b308
Posts: 5006
Joined: Sat Apr 15, 2006 5:48 pm
Location: North Worcs

Re: Steam Loco's - minimum radius curves

Postby b308 » Sun Aug 19, 2012 8:26 am

I think you may be confusing radius with diameter, something I used to do as well! If you have a 2ft wide board the maximum radius you can use to make a half circle (end of the return loop) is 11" which is too tight for most OO locos. For those second radius curves you'll need a board 3ft wide! I hope I've understood you correctly!

User avatar
GordonBigBoy
Posts: 73
Joined: Fri Jul 27, 2012 7:11 am

Re: Steam Loco's - minimum radius curves

Postby GordonBigBoy » Sun Aug 19, 2012 10:09 am

Thanks Roger and B308; that puts a different gloss on it..... I was calculating 50% of the diameter by mistake as you suggest. hmmm back to the drawing board me thinks .......

First radius curves needs 2x 371mm = 742mm which is roughly 2 ft 6 inches. So I need to amend the original question:

Can I get my large steam loco's (listed above) around a first radius loop if taken really slowly without rolling stock?
Gordon - A Really Big Engine

User avatar
Bufferstop
Posts: 12280
Joined: Thu Mar 11, 2010 12:06 pm
Location: Bottom end of N. Warks line

Re: Steam Loco's - minimum radius curves

Postby Bufferstop » Sun Aug 19, 2012 10:32 am

Why not put a turntable at the lower level. As it only has to turn 180 degrees it would not be difficult to automate. That's assuming you want it to happen "hands free". If you don't mind a bit of human assistance a quarter turn and a track coming straight out to a cassette, which can be pulled out and reversed is all you would need. In this arrangement the ramp down doesn't just lead to a turntable, but with spare cassettes to a whole MPD full of locos. The Peco loco lift makes an ideal cassette for this arrangement.
John W
aka Bufferstop
Growing old, can't avoid it. Growing up, forget it!
My Layout, My Workbench Blog and My Opinions

b308
Posts: 5006
Joined: Sat Apr 15, 2006 5:48 pm
Location: North Worcs

Re: Steam Loco's - minimum radius curves

Postby b308 » Sun Aug 19, 2012 11:12 am

Good suggestion, a cheap old Triang electric one would do the trick and I think they were pretty reliable?

User avatar
GordonBigBoy
Posts: 73
Joined: Fri Jul 27, 2012 7:11 am

Re: Steam Loco's - minimum radius curves

Postby GordonBigBoy » Mon Aug 20, 2012 12:49 am

Need to re-think this - I am really pleased I asked the question. Many thanks to all for all the tips and guidance. Food for thought and need to consider further as I have no luggage room for a turntable this trip. Watch this space. :?
Gordon - A Really Big Engine


Return to “Personal Layouts - Planning”

Who is online

Users browsing this forum: No registered users and 2 guests