Explain further Lee.
Did all the lights go out throughout the 4 carriages or just the carriage you were in and did they all go out or did a few (emergency lighting) remain lit.
I have been on 150's which have been idling whilst waiting at a station for the next duty when the engine has automatically shut down after a fixed period of not being under power. When this happens on the 150's the carriage lights go out except for a few which provide minimal emergency lighting running off the units batteries which there are on each carriage.
It is unusual to have an alternator of the size used on a sprinter carriage to fail as there is only one working part, the actuator, which is rotated by a pulley belt from the engine itself. It could be that there was a belt failure. It could also be that the alternator was not charging the batteries as a result of the pulley belt being slack tensionwise. This would result in the batteries running down and reaching a point where the electronics switch off the lights except for the emergency lights. Further draining of the batteries may switch off the emergency lights but you still need some power in the batteries to power the front marker lights and the rear red tail lights. I have even seen a 158 where the batteries were completly run down and even the red maker lights were out and this was at a platform face at Birminham New Street which was an a/b platform.
The alternator has replaced the dynamo in many applications and does not usually provide power directly to the lights or any other electrically powered equipment, the current generated is passed into a regulator box which regulates, as the name suggests, the power which is fed to and keeps the batteries charged which then normally powers all electrical apparatus.
Lee, in the incident you quoted was the ambient noise inside the carriage quieter after the Freshford stop. If it was then I would suggest that the carriage engine shut down whilst making the Freshford stop. This could have been for a number of reasons but the most common reason for this would be low engine coolant which causes the temperature to rise above a set range and a sensor would automatically cause an engine shutdown to prevent more serious troubles later if it were to keep running. I dont think the engines fitted to a sprinter is large enough to warrant it, but the larger diesels are also fitted with an oil cooler which cools the oil
in the engine sump and helps keep the moving parts of an engine cooler than they normally would. This has led to the development in recent years of the 5/50 grade of oil we now use in cars.
I dont know have many of the large Diesel engine manufacturers use them but I do know that SULZER have used them in the past. A TRIPLE PUMP. This is a single pump which has a three fold purpose, to pump the fuel to the injectors, to circulate the engine coolant through the cooler groups and pump the sump oil through the oil cooler. Boy if you get one of those go your in trouble big big time, you stop full stop. If you however have independent pumps then if the fuel pump went yes your in trouble again but with the other two you could still limp on to a suitable stopping place providing the operator noticed the rise in temperature in engine coolant or oil temperature, but then sensors may be fitted to give an audible warning of something amiss. The purpose of a triple pump is really an economic measure to save the engine from damage if any of the three fluids, fuel, oil and coolant has their flow impeded in any way.
In the Freshford incident I suspect it was no more than a lack of an inspection of the coolant level indicator when the unit was last refuelled and from start up on the morning of the incident until Freshford was reached the engine coolant had been within temperature tolerance to allow the engine to run but reaching Freshford it exceeded that limit and said enough is enough and shut down.
Now tell me the engine was running normally
Arent I being helpful.