As a cadet you will only be taught 1 type of overhead crossing which is called a Pole Crossing. However there are 3 types of overhead crossings that are used and the other 2 are called Natural Crossing and Mixed Crossing. (A Natural Crossing is where you would use 2 trees and sky hooks to make your crossing, and a Mixed Crossing is where you would use 1 tree and 1 pole to make the crossing).
To make a Pole Crossing the equipment you will require is as follows:
- 2 Poles (they come in 2 parts each).
- Spun Yarn
- Pegs (4)
- Guy Ropes (4)
- Hammer (2 if possible)
- Snips (2)
- ACL (Apparatus Cable Laying)
- Hard hats (as things can fall from height onto your head)
When putting up a Pole Crossing over an A Road you will need a 21ft pole either side, but when putting up a Pole Crossing on a B Road or a track you will only need to put up a 17ft crossing (unless the road is used by very high vehicles then you would use 21ft pole’s). You must consider what pole height you require before you collect all your stores.
- Decide on the positions for the pole basses (as illustrated in the fig)
- Assemble the poles and lay parallel to the road. The pole sections should both be laid facing the same direction on either side of the road.
- Once this is done you tie the cable with spun yarn in the grove at the top end of the pole (do both sides of the crossing) however you make a goose neck so there is enough slack of cable at the top of the crossing. The goose neck faces inwards not outwards towards the road (so basically it faces the direction of the cable that is on the ground)
- Once you have done the above you then continue to tie the cable down the pole (½ way down the top section then the middle and again ½ way down the bottom section of pole and then again at the bottom of that section of pole).
- Loop the guy ropes over the top of the poles (laying one guy rope to the left of pole and one to right of pole).
- When all this is done you have one man stood at the base of the pole with his foot at an angle with the pole up against it, plus that person will take hold of both guy ropes. Then another person stood at the top end of the pole and picks it up. (At the same time two other people on the other side doing the same). Once the pole has been picked up, both of the people at the top end walk towards the person at the base of the pole pushing the pole up. The person at the bottom also helps by pulling the guy ropes towards himself. When the poles are up you need to check that the cable that is crossing the road is taut, if it is not you will need to position the poles so that it is, once this is done one person stays holding the pole while the other takes the guy ropes 3 paces away from the pole and then takes 2 paces to the left hammers a peg into the ground and ties off one of the guy ropes to the peg. Goes across to the centre again by 2 paces then goes 2 paces to the right and does the same again.
- Now you need to provide more cable slack at the bottom of your pole crossing on both sides, so make a loop of cable on the ground and lightly tie it to one of the pegs.
- Label both sides of your crossing.
Joints are not permitted on the overhead or underground portion of crossings.
Crossings belonging to other units:
Do not use other unit’s crossings – build your own. Should you use someone else’s crossing and they recover their route first the chances are that they will cut your line to clear the crossing.
Post office telephone/telegraph and electrical power poles must (under normal conditions) be avoided at all times.