Its cause could have been overcharged brakes.
I encountered this problem at Scarborough on a passenger charter.
I attached the Poterbrook Leasing Deltic onto the charter, and did the required brake test,.
I did the BT from the rear coach and made sure the last three vehicle brakes were applied.
When we set off , the train ground to a halt outside the Signal Box, with dragging brakes.
As soon as this happened I knew we had a train of dragging brakes.
As a result I had to go pull the strings on all the coaches to get rid of the air is the system.
Having done this, I performed a roll by of the train to ensure that the wheels were rotating properly.
This was done in conjunction with the driver.
After this there was no more dragging brakes.
This was a case of RIC DIC pull the wires , and watch the blocks fall off the tyres.
I found that continental ferry vans, brakes were slow to come off, and it was not uncommon to see the last vans skidding on the track as they passed by.
After a couple of yards the blocks would fall off the wheels would rotate normally.
Shunters were mandated to watch a train they had prepared do a slow roll by test to ensure that all wheels of the train were rotating and hand brakes lifted.
As all locomotives had a spy in the cab, if a problem was found with the brakes on route, a download of the engine would be taken, to show if there had been a brake test and a roll by. If not the person who prepared the train would be in the crap, with a good chance of geting the sack.
