You have seen the link HO scale dimensions over the full size aerial shot as another aid to plan this layout.
I had started on a paper plan using some dimensions of the aerial photos as shown in the link above. I wanted to do a mock up in full size of the layout from the level crossing to the signal box.
To aid this I re sized the aerial shot, grey scaled it and rubbed out the dimensions. I then used good old MS PAINT to print it out so I got 25 pages of it blown up. This was almost scaled to my normal paper plan scale. Yes it was very blurred but enough detail to draw lines on it. It took a bit of jigsaw skill to patch the paper together.
With this I then checked the distance from the road to the signal box - 8ft. On this blown up plan the dimension was 7ft - a small reduction in size. This would not be a bad thing. However my main concern was the width of this layout.
I wanted to make a mock-up on a roll of paper. My intentions was to narrow up the layout. To do this I drew in the two mainlines. Then using #7 point angles placed the two points into the yard. Next I took a rough width from the BG mainline to the track with the double slip. This was transferred to the paper roll. I then got curve templates so I could make a "S" curve.
This has resulted in the distance from road to the signal box to be about 6ft. I have saved 2ft on the length. width wise is still an issue (and always will be) - I have track centres in the yard at 45mm. If I we planned the width to have the oil siding just on the edge , so we had room for the signal box as one end, and then had the cement road as the other 'main' extreme - we ended up with 3ft. That means little scenery on the board, and does not account for the angled industry sidings off the double slip. To me a all track layout is a problem.
We could cut a few roads out of the layout. This may compress the width by about 3/4 of a foot. I haven't drawn this up yet to see what real width I'd come up with.
The Industries off the double slip are a problem. If that side of the layout is the public side, it means a angled peninsular, or somescenic area which is good for front railway area but means more bench work. I do not think we can have the yard side at the back for the same reasons.
For a larger view click on the image.