Surveying the track levels.
Several people asked why we were doing this. The reality was probably stranger to watch than the pictures suggest, but hopefully the end result will be a railway that has slopes that aren't too difficult to ascend or too alarming to descend.
| Having cut out a route for the track, we worked out where the slopes were by taking the levels of various points on the route. We made our own giant spirit level with a length of hosepipe with two plastic bottles (with the bases removed) attached to either end and filled the whole thing with water We then put in a series of canes and measured the distances between them along the track bed rather than in a straight line. |  |
A final cane was placed in the centre of the track and a marked with a horizontal line.
Holding one end up to the cane with the base level, we put the other to each of the canes around the route in turn. By adjusting the outer bottle until the water level at the other end was level with the base mark, we were able to put marks on all the route canes that were at the same level.
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| Measuring the height above ground allowed us to produce a height profile of the route. This showed us that our steepest slope was 1 in 30 and our gentlest was 1 in 150. Our aim was to adjust the levels so that the steepest was only 1 in 50. |  |
| Early June, 2008 and the first section of track bed is dug out. The vertical peg is to help determine the correct height for the boards shoring up the sides, with a horizontal line drawn on it using the figure collected above. To stop rain, heavy feet, bicycles and the like damaging the edging before the sides are properly secured, they were wedged apart using a sleeper and two pieces of board an inch thick. We hope this will allow a large enough gap between the sides and the sleepers. |  |
Mid June. Following discussion with a friend who took a look at the above, we decided to widen the track bed to allow three inches either side of the sleepers. After posting a question on the Yahoo 5 inch gauge group, I learn that others have allowed a gap of four inches but think that three should be okay. Most seem to have used smaller ballast than the 20mm we're hoping to use (on the grounds that we can obtain this at a reasonable price). One reply from Australia mentions heat expansion causing a vertical increase of a foot on hot days. Fortunately that's unlikely to be a problem in the UK! |  |
