The engines are replaced as necessary, either when their time is due, or in the event of a failure. There are standards to be met with such things so there is no doing it 'on the cheap'. It wasn't a fuel pipe, and the investigation will reveal what went wrong, but you're right in that something like a piece of dislodged ballast can damage things, especially at high speeds.
Probably a sloppy choice of words. ''Cost efficient'' is what I should have typed then!
My intention was to include the structure of the maintenance regime of high performing DMUs (specifically the QSK19) in connection with their reliability, while also ruling out the idea of ''re-design it!'' too as that's the usual-unrealistic scenario that gets plastered across this forum, as has already mentioned.
There must be an element of financial risk somewhere along the line with quality taking a hit. I've seen some nasty damage on ''fresh'' engines lately. Just makes you wonder what the deal is and what quality controls are in place.
On another note we've had a unit come back with a bin bag wrapped around a turbo!
Most reliability issues go unnoticed by most of the world. It can be something as simple as a wiring design that can bring performance down yet people still try pin point it by whether there's an electric motor or a hydraulic transmission driving the axle...
