Trackbed Surveying and a Spiral.

The garden has always appeared to be reasonably flat but looks can be deceiving. There was only one way to find out if my proposed track layout would be viable and that was to carry out a survey.
I hammered in pointed sticks every 2.4 metres along the proposed route and then used a long spirit level to work out height differences. So far I've only done this for the right hand side and the bottom of the garden.

Survey Stations

Here are the results.

Survey of the Right Hand Side of the Garden

Survey of the Bottom of the Garden

This means that I will be able to lay the line at ground level with modest gradients well within the recommended guidelines for garden railways.

I haven't carried out an accurate survey of either the left hand side or the top of the garden but I have worked out that there is a significant drop-off at the top left corner. A very rough calculation has shown that the gradient for a ground level line across the top of the garden would be an unacceptable 1:20 or thereabouts.

This means that where the branch line begins at Stoke Works Station it will need to be a quite a high embankment. 

I'm now toying with the idea of dropping the line back down to lawn level by incorporating a spiral. I've got plenty of time to make the decision as I will not be starting work on this section of the railway until next year.

Proposed Spiral