High Pressure tube leakage.

                    Recently the failures of Diesel locos due to crack in HP tubes have been observed. Drivers were unable to cut off fuel supply by blocking control rack of affected FIP.

                    HP tubes breakages are caused due to excess vibration, crack, use of unapproved make HP tube etc.

Action to be taken:

          Maintenance of HP tube

1.    Only HP tubes of approved make are to be used, other HP tubes should be weeded out.

2.    DPT testing of HP tube should be conducted in section itself during M_24. In situ testing during M₁₂ should be carried out.

3.    Handling of HP tubes must be done extremely carefully as slight dent during handling/transportation becomes a stress notch point for propagation of crack. Suitable HP tube carrier and storage rack (wooden/rubber/plastic) should be developed.

4.    Profile checking & high pressure testing should be carried out in testing gadget in section itself.

5.    All HP tubes above 10 yrs. of age should be weeded out from main line locos, these tubes after testing can be fitted in locos working in inferior service.

6.    Grommets must be renewed during M₂₄. Condition of Grommet must be checked in every schedule & perished Grommets should be replaced.

7.    Vibration measurement of HP tube should be carried out in M₂ and above schedule. All locations showing higher vibration should be attended & vibration level should be brought down.

Checking fuel delivery at zero rack travel

Blanking of FIP in case of HP tube leakage should be done en-route.

All FIPs should be tested in section for fuel leakage when control rack is locked at zero by pump latch. It should be ensured that there is no HSD leakage when rack is locked at zero. This is an important fire prevention criterion.

“Move the control rack towards stop position and engage the latch with the slot provided in the control rack. Run the test bench at 200 RPM. There should be no delivery. ” (Ref- Page No. 11 & 12 of Instructions Manual on FIP).

It will ensure that even in case of mid-section HP tube breakage, drivers are able to complete the trip and failed HP tubes can be changed at Trouble shooting points.