Rowlands Modules – Setting the Standard

During 2013 Gareth Jones, one of our members, led an initiative to develop the standard published below for the buildng of ‘modules’ that can be brought together to form layouts either by an individual or by groups of people wanting to create something different every time they meet at an exhibition or event.

As Gareth said to those involved in setting this standard with him “First of all, many thanks to you all for joining me in this vision, I hope we can create something great between us”.

At the National Garden Railway Show

The modular layout has appeared at the National Garden Railway Shows at Peterborough Arena from 2014 onwards. Brian Dominic has kindly contributed these photographs from the 2015 show.

Baseboard Dimensions

The most important question is layout height. We are indebted to Bryan Mathews for proposing that the Hants group layout, ‘Much Crymblyn’ be modified to be part of a larger Modular Layout. He is going to arrange that clearances are eased such that it will accommodate the largest current ‘normal’ SM32 Rolling Stock.  Unless you know different, this is the 135mm width of a VoR Swindon Built Loco, and the 195mm height of the Diesel Loco ‘Chattenden’.  ‘Much Crymblyn’ currently is 935 to the top of the rails, or 925 to baseboard level.  With the addition of threaded height adjusters, this will bring it to 950mm to baseboard level, 960 to Track top.

Width of board ends in multiples of 150 from 450mm upwards, 450, 600, 750, etc.

Track centre from front edge of board, 150mm. Subsequent tracks at 150mm centres from this.

Baseboard Length 1200mm being the standard, double or half lengths being useful too. If we are building the layout at a show in Rowndy-rowndy form, then this is important.

It we configure in end to end with return loops, then lengths are not important.  If adapting a current layout, building ‘Adaptor Boards’ to connect to standard modules, it would make sense if it makes the whole assembly a multiple of 1200mm.


PECO SM32 track and large radius points to be used at board ends, this will enable common connecting. It will also allow us to electrify the main circuit. If using other sorts of track, please make sure rails are insulated from each other, on the main running lines at the very least.

Track to end 50mm from the end of the board.  Joints to be made with ‘drop in’ 100mm lengths of PECO track.  In practice we will have a range of short pieces in 1mm increments from approx 97m to approx 103mm.


Clearance on straights and curves (R1697 min) to be 150mm wide (75mm each side of track centreline), 200mm tall.

If making curved boards, radius to be R1697. (There is a geometric reason for this). This is approx 5’ 7” Radius.  5’ Radius to be the minimum with reverse curves avoided.

Baseboard Joining

Modules to be joined by 2-off 3” steel, screw type ‘G’ clamps. Minimum Baseboard frame depth at the ends to be 76mm including top surface.  Where deeper, cutouts to be incorporated to accommodate the throat of the clamps.


On my initial units, I bolted end boards, joining to baseboards with tracks facing inwards.  This forms a solid cube.


See photo. The Dia 7mm holes for this can be used as secondary methods of joining the boards together.

Legs to be of such a design that they don’t affect the placing of the clamps.  Cross bracing to be set down from the top of the boards.

Baseboard Joining – Optional Bolted Method

To reduce the amount of clamps we need to use joining the baseboards together, an optional system of bolting with M6 Bolts, 6mm Penny Washers and Wing Nuts has been drawn up. This system does not suit all baseboards; however, it does work on some boards, and has been successfully used by John Whitbread and Gareth Jones.

Baseboard end

Passing Loops

Passing Loops to be capable of accommodating an average 4-Bogie Coach plus average loco – min.

4 x 44’ + 30’ = 206, Divide by 19, = 11’.


Please ensure a reasonable standard of carpentry, in particular, baseboard mating faces to be square to the tops.

As my woodwork teacher memorably told me during my first ever lesson – this is not a square, holding up what clearly was a Carpenter’s square, with steel blade and wooden stock.  He then flamboyantly checked it by scribing a perpendicular line from the edge of a plank of wood, then turning the square over and scribing a line on top of the previous, checking that they didn’t diverge. THIS is a Square, he announced triumphantly!! That lesson has stayed with me!  Likewise, he promoted checking tape measures against a quality steel rule – the end stop is prone to bending.

Typical Baseboards

These are very basic, and I hope you will all quickly stray away from the ‘Track parallel to the baseboard edge’ look.  Please keep in mind that it is the ends that need to be modular, not the content in between, within the limits of clearance of course.

Steam-up area

The following two photographs show progress on a steam-up area, which made its first appearance at the 2015 National Garden Railway Show, providing a much-needed facility for the modular layout.

Corner Specification

The following two drawings have been produced to enable a complete circuit to be built for operation at shows etc. Click on the link below either of the thumbnail pictures below to download a pdf copy of the relevant drawings.


New Baseboard Drawings – Smaller Radius Curve

In response to a call for slightly smaller radius curves, Gareth has drawn these two baseboards, 2 sizes, ie 300mm less radius than the current ‘Standard’ Curve. These are approx 4′ 7″ Radius.

Gareth has drawn them as standard 450 width and 300 width; the latter will allow reverse curves to be made with a suitable joining transition straight between them (which he will draw next). A great advantage of these new drawings is that both can be cut from a standard 1200 x 600 sheet of plywood.

We have a shortage of curved boards – hopefully these will inspire perhaps the newer members to get cutting and sawing! As Curved Module Owners, you will be very much in demand!

Tony Bird has also drawn a variant with double track, 1397mm and 1247mm radius.

1397mm radius curved board, 300mm width 1397mm radius curved board, 450mm width 1397mm and 1247mm radius curved board, 450mm width


Tony Bird has also published a video illustrating his method of constructing the 1297mm & 1247mm double track boards – this is one person’s interpretation of making modules, and by no means the ‘official line’.