Plywood Box Section or L-Girder baseboards?

[6029 King Stephen]

As some may know, if you have read my recently restarted thread, I am looking to build an N gauge layout based on Tavistock North.  I had previously attempted to build the layout using 18mm ply that was 175mm high by 30" wide for the crossmembers and 100mm by 48" for the lengthways member.  The 175mm was arrived at because I was allowing 100mm to allow the use of Tortoise point motors plus the 75mm height of the viaduct that is located at the west end of the station.  I got as far as laying an underlay of 3mm closed cell foam and pinning the track down on the scenic section and getting almost the whole way through the hidden fiddleyard when I had to return to the UK and there was an issue with having anything wooden, fumigated and this was going to cost too much.  I had also had to compromise on the track layout because when I built the first attempt, the mainline snakes from the front edge of the layout towards the centre and ascends an incline of 1 in 75.  This is OK because the west end also inclines at 1 in 75.  The problem was that with the east end line being about halfway across the board, there was insufficient space to have a reverse curve to the fiddleyard.  For the Mk2 version, I got rid of the curve and so the layout became the more traditional oval circuit.

 

For the current, Mk3 version, I am spending more time on the planning.  I have printed off the Templot plan and will be taping it together.  I will then buy a couple of sheets of 6mm ply and lay the plan on this and mark the outline.  I will then cut the ply (like a cookie cut trackbed) and have that set on risers to set the trackbed at the 75mm height of the viaduct and add extra to account for the inclines at each end.  My question is, which method of baseboard construction do you think would suit my layout plan best?  I have narrowed it down to either the plywood box section, with or without 50x25mm spacer blocks, with 50x25mm risers and 25x25mm cleats to support the trackbed or the L-Girder system with 50x25mm cross members and 25x25mm cleats.  I am looking to stick to the prototypical plan that includes the curved inclined mainline but increase the width of the layout, where necessary, from 30" to 42" (or its metric equivalent).  Whereas for Mk1 and Mk2 the total length was 12', I have been able to extend the Mk3 version to 15'.  I am also using Peco under baseboard point motors and sticking with the 3mm foam between trackbed and track.

 

I am leaning toward the L-Girder as it seems to offer the great flexibility.  The layout is for personal use and will not be exhibited.  I have built work bench that is 15' long x 32" wide that will double as the support for the layout, when in use and for use with my woodworking tools when doing any projects.

 

Thanks,

 

Steve 

Edited April 11, 2018 by 6029 King Stephen

[Campaman]

I have use L girders and have found them to be a very flexible option if you are building with cookie cotter trackbed.

 

They are also very strong, I can sit or stand on my L girders which are only supported by 4 legs along a 16 foot length, so you don't have to worry about leaning on the girders while working on the trackbed and layout.

 

Cross members and risers are also easy to move and adjust if you have to for levelling, or changes.

[Joseph_Pestell]

Another vote for L-girder - especially in the context of Tavistock North with its extreme embankments, cuttings and viaduct.

[Yardman]

I’ve built both over the years. I found L girder more suited to a home fixed layout while a plywood box baseboard more suited to a portable exhibition layout. With either type I still fit all track bed support fixings from underneath so fixtures can be moved to clear switch machines, uncoupers, signals etc. if needed. Something always seems to end up in an awkward place. L girder allows for more distance between legs and a more open baseboard structure together with a more flexible baseboard shape (they don’t need to be rectangular). A plywood box makes it easier to fold up legs within the structure and bolt multiple baseboard sections together for a bigger layout. As the saying goes, horses for courses.

[6029 King Stephen]

Thanks for all replies and advice. I think I will be going down the L-Girder route.

 

Regards,

 

Steve

[DCB]

Respect, that is an awesome project, I took photos of the viaduct last year as I way impressed by the way the viaduct stands so high on the valley side.

Again a vote for L girders especially for this location, there is plenty of room for a big sturdy structural beam in the viaduct so have fun. Looking forward to seeing pics of the finished layout.

[The Johnster]

If I were starting Cwmdimbath again from scratch I would be considering L girder with the vertical part to the top, or even as sort of sideways T section version; easy to construct even at my level of carpentry, strong, and a ready made support for your backscene.