Prior to any destressing operation the track must be regulated, broomed and cleaned to ensure the fastening assembly is clear of ballast.
In all cases, care must be taken to ensure sufficient clearance exists around the FASTCLIP assembly, preventing accidental collision between the assembly and any regulating equipment.
The diagram describes the safe working envelope that has to be provided around the fastening by regulating equipment.
The recommended procedure for destressing is as follows:
1. Extract the FASTCLIP’s to the ‘parked’ position, either by machine or with the extraction tool
2. Where rubber pads are used, lift the rail and fit under rollers (plate rollers) or VORTOK VSR’s (see section Use of Stressing Rollers) between the rail pads and the rail foot at every 10th sleeper
3. If the site is curved fit side support rollers or VORTOK VSR’s or VORTOK VSR’s (see section Use of Stressing Rollers) adjacent to the underroller on the inside of curves to maintain control of the rail
4. Tension the rail
5. Install clips adjacent to the tensioning device, securing the rail position (approximately 30m of rail)
6. Remover rollers
7. Continue to install the remaining clips
Various machines types are suitable for destressing, but the most commonly used as follows:
These machines connect to Road/Rail excavators.
Hand Held machines for Destressing or Rail Changing
These machines are specifically designed for rail changing or destressing. The machine pictured is a Geismar AP11.
A Handtool is also available for destressing:
Clip Extractor - Destressing
1. Locate the tool in the shoulder with the handle held back as shown
2. Ensure the tool is located correctly in the shoulder
3. Push forward on the hand until the clip reaches the back stop (parked position). This is the position for destressing. The rail is free to move and all components remain captive on the sleeper
To fully remove the FASTCLIP, continue to push forward on the handle. The back stop lifts and the clip is withdrawn to the side post insulator change position. Push further, and the clip can be removed completely.