scope:

The total number of scarf joints currently installed in the network is not known. 5 pairs were recently installed as part of a track enhancement 3 on N&E route and 2 on the NOC. 13 are known to be installed on Liverpool DU. 

No further installations will take place and all works planned to utilise scarf joints have been instructed to replace these with suitable, conventional 4- or 6-hole IRJs. No works have been identified as being at risk from this suspension.

Purpose

To inform Network Rail staff that;

1. There is a current UK wide, suspension of installation of Isoliers to B IVB 30° Scarf Joints. 

2. There is currently no valid competence to enable the Ultrasonic testing of scarf joints in CEN60 rail. 

3. The ultrasonic testing (UT) procedure U20 that does exist, does not scan the centre half hole, and therefore does not provide a complete test for defects that could initiate from the centre half hole.

4. The UTU does not normally provide an appropriate test for scarf joints.