Note this post has been updated following the loss of photos on RMWeb

Converting a loft for a model rail layout

The only internal timbers in my loft are three ties at roughly chest height you can just see all three in this shot of the loft as it was insulated:

 It seemed logical to use this to support my layout.   Timber in 1946 was clearly of better quality as these are just 50x100mm in section and yet they stop the roof sagging by being connected to purlins around the edge of the roof.    I couldn't easily move the tie in the middle of the picture (the one with the red pressure tank next to it) and I would have to duck under it hence my need to automate my layout. However I could make a feature of it by making some sort of figure of eight maybe to change direction. As I mentioned in my last post I also got my builder to add in in some more 100 x 50 beams at right angles to the existing ties them to further support my intended layout. You can just see three of them right over the back coming out for the foil to meet the furthest tie.

Given the physical constraints of the loft I would really need to think about a suitable track plan. I know a lot of people rely on a few sketches or marking stuff out on the boards once they are in place  but I am a software engineer and I designed our house in CAD so how hard could a layout be?  Well actually I found it a very challenging and interesting exercise in its own right.  I used a freemium SCARM track planning solution which I bought once it was released.  It takes a bit of getting used to but allows for accurate positioning of flexi-track, both to limit the tightest radius (750mm in my case) and to set inclines precisely as well.  I did buy the trains simulator too and while there are no UK trains on it, it allowed me to judge how the real thing would work:

The layout

Before I get to the layout design a word on my design goals -

• All my layout should be in view with no hidden fiddle yard as I knew I'd be operating it from  different positions with laptops  & phones over wifi and inviting a few friends to have a go as well.
• I wanted to loosely model Hastings where I grew up but back in the 1930's when steam engineering was at its height.
• There should be lots of options for routes mainline, branch-lines with and some freight working too
• My layout is pretty big  and those beams are in the way so automating the points would be essential. 
• I had no legacy equipment so I could standardise on the latest thinking. For example I was impressed with  the great point motors and systems from DCC Concepts. and their excellent advice on wiring for DCC
• I wanted freedom to stop and start trains wherever and have them moving at prototypical speeds so DCC would also be used for train control, and I wanted to explore software control from a touch screen like Hornby Railmaster possibly with Hornby Elite as well (which I have now replaced with a Rocco Z21 and iTrain as detailed n this post).  
• For the most part I'd be using 50mm track centres as there are no issues with overhangs on rolling stock at 750mm radii and this is what Peco 75 points are engineered for.

After many iterations my layout design looks like  this:

• The blue outline is the baseboard:
• The centre section is sitting on one of that exiting ties I can't move so you have to duck under it anyway. 
• The access hole top right is need to reach the edge of the layout in the top left (NW) corner.
• The loft hatch is not shown but comes up in the cut out are in the SW corner (so lower left). 

SCARM this in 3D complete with the supporting timbers where brown indicates existing structural ties/purlins and the orange the new timbers added by my builder, so you can get a better sense of your design

However the tools for creating buildings in SCARM are quite weak so I have just made a rough copy of Hastings station as was in the 1930's and designed the station to hold a  pacific loco with six coaches .  

I have to admit the track plan does look a bit like a toy train layout, however as I said already, the radii are much larger to enable fitting detailing packs to locos, and to permit close coupling of tenders and coaches.  One other thing I did in SCARM that sort of worked was to try and plan around the supporting timbers

In the 2d view layers can be hidden to aid clarity.  I have layers for the various design elements on the plan:

Notes on the Design

Essentially this is an two line oval track with a branch lines which cross over to change form one track to another.

The three  branch line sections shown in grey are those likely to need auto reverse units as will the turntable. There is a turntable as I'll be running express steam trains and I have added to long sidings (in yellow) to feed that which will double as storage for  rakes of coaches or wagons.

The two into one siding at the bottom of the layout will server some sort of industry - possibly a brewery!

Inclines

Hastings is hilly so I wanted at least a couple of inclines with bridges and so on.  The trick to setting up these is to create enough room to get one track over another at the  top centre (north side) given that I want to use 2% inclines. To achieve this, the southern end of the layout (the bottom edge of the plan above) at about 30mm above the lowest level (0mm) of the Northern centre section end.  In this view of the middle of the layout you the right far side is 30mm height so far double track climbs 60mm to give 90mm clearance over the track off camera on the left. The track in the foreground drops 30mm as it goes into a tunnel to connect with the bottom level of track.

This gives a rough idea of how the track passes over itself and in this view I have put in a road bridge scenic break to show what this will look like:

One snag with this use of inclines is the sidings (in yellow on the diagram above). They have to be nearly level so unattached rakes of wagons and coaches don't roll anywhere and the same applies to my station. SCARM helps with this but I also tested what the maximum incline I could have through the station without coaches moving and then built that into the design. 

So now I could get busy with actually making the baseboard and that's for next time