Top speed would be 75mph (max speed of a 66!)
I have seen a DB 66 working an ECS move from Neville Hill - Doncaster Wabtec in the past so could be something similar to this as I would expect a 67 to be on the front if it was a 'rescue'!
The 66 could shove the train, at a very much reduced speed.
The assisting engine would have to be placed at the front of the train as soon as possible.
Some years ago, alot of the main to main x overs were removed.making it difficult to run round the train and come onto the front of it.
Once on the front, the train would have to have an brake test, and then go forward at the maximum speed of the 66.
At Christmas time in 1984, I was the guard on a Sheffield to Leeds parcel train.
After coming onto the GN at South Kirby Junction the train engine expired and was a total demic.
As a result we had 4 coaches on the Down GN and 3 coaches up the bank towards Moorthorpe Station.
Leeds sent a class 47 to rescue us. This engine went upto the goods loop at Moorthorpe, reversed out of the and crossed over onto the blocked line using the main to main x over at the station.
Protection was carried out from the foot crossing at Moorthorpe station down to the rear of the failed train
The dets were then picked up , and the 47 was conducted to the rear of the failed train and attached to the rear coach.The tail lamp was removed and stored on the class 47 and a brake test was carried out.
After all this was done, we set off at a very quick pace up to Wakefield Westgate Down platform road, where we hooked off the assisting engine, ran it round in the Station and coupled it up to the failed engine
Then we set sail into Leeds at line speed of that train.
Instead of finishing at 0100hrs I got home much later on.
If we worked at Leeds we were paid 4 hours travelling time and bus fares.
The date was 27/12/84. Leeds turn T457. Work 1J02 to Sheffield with loco 45026.