Hi Scott, thanks for your interest in this subject.

I cannot be certain how our Terbergs are "plummed in" because I am a "only a driver" and thus have no access to the delicacies under the panels. I do have extensive experience of heavy trucks for road use and still find it hard to believe that a simple electrical problem renders the tug inoperative and immobile. Further that the spring brakes only are indiscriminately applied, without the benefit of ABS or load sensing.
One can think of many situations where an immobile tug could cause danger, particularly if the electrics have caused the original defect and possibly started a cab fire while on board ship!

I have discussed the dangers with a Terberg fitter and he gives me every assurance that the vehicles are safe to use, much on the basis that it hasn't happened before.

I have asked for the tugs to be brake roller tested (foc & on site) but have been assured that spring brakes "cannot fail" therefore such a test (to verify equal spring brake performance) is not required.

Any further comments would be welcome.

Hi rod, I have come across a system like this in a Terberg dock truck before, the vehicle I worked on had the electrical side disconected to stop the brakes operating automaticly.

you state that the isolator was faulty so the hand brake could not be applied, but the truck I worked on had an air operated hand brake valve that was completely seperate to the air solenoid that operated the auto brake.