Carriage Dimensions - clearance on twin track modules

[IanT]

I'm currently doing some design work on twin track 'curved modules' and one of the issues is going to be clearance on the various standard curves we recommend. I've had a few enquiries in this area from Members building garden layouts and in the September Issue I re-published Alan M's June 2002 article on G3 "Track & Lineside Structure Clearance".

To support his recommedation, Alan physically used his BR Mk 1 carriages to check clearance on curves, specifically looking at the 'throw' from the track centres to the outside corners of the coach (see diagrams on page 6). Because this is an important issue, I used AM's coach dimensions to look (using a CAD model) at clearance between two passing coaches on various curves using the existing track spacing. They clear but it's only 12mm and I'm not convinced it is enough.

I'm planning to build a spreadsheet to calculate clearance on various curvatures (should be easy but will need some refresh of my long unused trig) but I need to check on "worst case" senarios with respect to various carriage (and possibly bogie) stock. Whilst I have data for some stock (mostly pre-grouping) - I don't have too much on more modern stock, such as the BR carriages used by AM.

What I need are some of the larger prototypical carriage/bogie stock samples to check - giving the following key dimensions: body length, body width (at widest section), full length over buffers and (most importantly), distance between bogie centres (I will assume they are symetrical). I suspect that it's not simply the length that will be crucial, the size of bogies will also play a part. I'd like the data in the prototypical "feet & inches" please

BTW - I have NEM 103 - but I want to check clearances against a British loading guage and see if we can produce something (hopefully simpler and) specific to our needs.

Thanks for your help with this.

IanT

     

[Andy B]

BR Mk3's:
Length over headstocks - 22150mm (72' 8")
Length over gangways (coupled) - 23000mm (75' 5 1/2")
Max width (over stepboards) - 2743mm (9' 0") - waist is only 3mm narrower
Bogie centres - 16000mm (52' 6")
Bogie wheelbase - 2600mm (8' 7")

If anyone ever builds a rake of GCR 'Barnum' coaches, I think these would probably be the ultimate test.
I think they were 9' 6" wide, but can't find any dimensions right now.
Will keep looking.

Andy

[cabbage]

Well the biggest locomotive that I am planning is the NBL Gas Turbine...

NBL GTEL  70 feet over buffers and 34 feet 6 inches between pivots.
Deltic 69 feet 6 inches over buffers and 45 feet 0 inches between pivots.
Falcon 68 feet 9 inches over buffers and 42 feet 0 inches between pivots.

Have fun playing with Chords...

As far as I know -there is only one member who has produced a "Garrat". If you really want to spruce up
your trig then try getting your mind around the cornering actions of a "Klose" or a "Golwe"...

regards

ralph

[Andy B]

Found some Barnum information:
Length over headstocks - 60'
Length over coupling plane - Not found yet, but likely to be around 63'
Max width (over stepboards) - 9' 0"
Bogie centres - 41' 6"
Bogie wheelbase - 10' 6"

The wheelbase on these would certainly add to the overthrow quite substantially!

Andy

[Andy B]

Remember that simply using the 'biggest' key dimensions won't necessarily give the worst offending vehicles in terms of clearances.
End tapers have got more pronounced as vehicle dimensions have been maximised within a given loading gauge.

Andy