Thank you all for taking the time to respond and for the information supplied.
The reason for my enquiry was to try to establish if there was a similar schedule of dimensions set out for Ireland as the BRMSB set out for standard gauge railways for Platforms, Buildings and Bridges.
If you watched the model railway challenge programme on Channel 5 on Friday evening you would have seen that one of the teams had to realign a section of curved track as coaches on concentric curves collided with each other due to inadequate clearances being provided.
American and European standards set out requirements for curved tracks. I am not aware of any OO gauge standards available for curved track!
The BRMSB for dimensions for Platforms, Buildings and Bridges as set down for standard gauge railways are not I believe appropriate for models of Irish railways due to the fact that Irish prototype coaches were wider that their standard gauge counterparts.
For example the widest coach used in Ireland were the Park Royals which had a maximum width of 10 ft 2 in being 8 in wider than the standard coaches used on standard gauge.
I fully appreciate the point about clearances having to be increased to cater for curved and canted track and also vertical curvature.
I believe the vehicle (in revenue earning service) with the greatest distance between bogie centres are the pocket wagons with a bogie centre distance of 17000 mm.
I purposely stated revenue earning service to exclude departmental stock such as a ballast cleaner or the like
The standard distance between bogie centres for Intercity stock is 16000 mm and for Suburban / Commuter stock is 14100 mm approximately.
Intercity stock generally has the passenger access doors at the ends of the vehicles which can be problematic for stepping gaps when the platforms are curved e.g., Cork where as Suburban / Commuter stock generally have the (wider) passenger access doors at or near the bogie centres to minimise the effects of centre and end throw when platforms are curved.
On a section of curved track a vehicle will need additional clearance to cater for the centre throw (overhang at the middle of the vehicle) and end throw (overhang at the ends of the vehicle).
The European standard for model railways uses a value equal to twice the centre throw to widen the interval between tracks. So following the same logic this would equate to a vehicle overall length of just over 24 metres which is a little longer than any vehicle currently in use in Ireland.
Mention has been made of the "big overhangs at the front" and I believe that ICRs have an overhang from bogie centre to cab end of 4000 mm, so the maximum end throw such a vehicle would generate is the same as a vehicle with an overall body length of 4000 + 16000 + 4000 = 24000 mm as stated above.
On a section of curved track the interval between the tracks must be increased by an amount equal to the sum of the end and centre throws in order to preserve the clearances.
Similarly if there is a platform on a curved track, the lateral clearance needs to be increased by an amount equal to the end throw or the centre throws in order to preserve the clearances.
Depending on whether the platform is on the inside or outside of the curve. Allowances for the effects of cant must also be made.
I apologise if the above is long winded, but as someone who worked in 1 to 1 scale for over 40 years and am how hoping to build an OO scale model railway using RTR Irish equipment I am anxious to get it right first time!!
In due course, if there is a desire for it, I will post details of the standards I have adopted (together with the reasoning for same) for the benefit of the group.
I would only be setting out recommendations for the area above rail level and many recommended dimension will be specified from track centre line rather than a rail, as this will suit people who use 16.5 mm track for RTR stock and also people who have adopted 21 mm as their standard .
Vertical clearances will of course be relative to the top of the rail.
It is my belief that RTR stock has wheels compliant with both European (and American standards) and are designed to negotiate a minimum radius of 438 mm (R2 in sectional track).
I look forward to any further views and in particular if an Irish version of the BRMSB standards for Platforms, Buildings and Bridges would be useful to the group.
Thank you for taking the time to read this post and should need any clarification etc. please just ask.