They operated all services, freight and passenger, and were the NS' main locomotive until the arrival of Class 1600s.

1129 was involved in an accident in Westervoort in 1978, this locomotive was not destroyed, and was put back in service.

After the 1978 accident, the locomotives were rebuilt slightly to improve driver safety, with a crash-absorbing nose ahead of the cab inspired by the French 'Nez Cassé' design.

In operation, cooling fans in the engine compartment produced a remarkably loud roar.

For these reasons the locomotives were downright hated, and until 1980, their drivers were paid a special bonus, one originally designated for dirty or unpleasant work.