Some of our investigative work
Locomotive low water shutdowns
A 16-cylinder locomotive experienced multiple periodic low-water failures. Testing could not find any leaks. Analysis and system testing found it failed only after 35 minutes at full load. This gave the appearance of a random failure, as it would only occur in certain places.
Testing at pressure points confirmed a failure process: sight glass bubbles, then a bounce, then pressure rises at the water outlet, and eventually a header tank overflow.
Static cylinder pressure testing could not locate the fault. A series of elimination tests led to removing one cylinder. Pressure testing the cylinder after an hour at 550 kPa finally revealed a minute crack in the head that, when the cylinder was hot enough and under full-load pressure only, forced cylinder pressure into the water system. The picture is of the soap bubbles locating the crack.
The problem was found, and a new diagnostic process was implemented that identified several other locomotives with the same random issues.
Fleet bearing failures
A new fleet of wagons began suffering bearing failures across multiple batches.
No single batch or manufacturing cause was identified, and the suspect was thought to be faulty seals. Analysis of the bearing when stripped and crackle testing of the grease identified moisture in the grease in affected bearings.
This was eventually traced back to likely contamination during transport of the pre-greased sealed bearing from the manufacturer to the assembly.
Warranty claim proven.
Train emergency brake applications
An ECP train was having random emergency brake applications after an initial brake application. Extensive testing found no faults with the train. Log analysis revealed, in one log, a one-second gap between the pneumatic and ECP systems commanding the emergency application, indicating a pneumatic problem.
Further ECP log analysis showed it was coming from a wagon in the second half of the train. This could be an emergency portion or a vent valve. A series of component cutouts to eliminate possible wagon causes was performed on each wagon until the issue was traced to one of the last wagons.
The problem was contamination in one of the emergency portion slide valves, which allowed a small air leak into the emergency release spool valve.
Mystery solved.
Centre liner damage
Centre liners were noted to be distorted and flattened on some wagons.
The liners are Neoprene and wear very well; however, Neoprene is also susceptible to breakdown from sulphur.
Due to cracks in the top deck, water had infiltrated into the centre sill and, with some cracks around the centre casting, had infiltrated into the centre liner. The water, washed over by coal residue, had high sulphur levels that affected the liners.
The issue of cracks was identified, and rusting of the centre sills was identified early.
A mysterious fault was traced back to multiple other developing faults.
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