counter-steam, back-steam
Машинист дал контрпар, чтобы остановить состав.
The locomotive engineer applied counter-steam to stop the train.
Контрпар помог быстро затормозить тяжелый поезд.
The counter-steam helped bring the heavy train to a stop quickly.
Без контрпара локомотив не успел бы остановиться.
Without counter-steam, the locomotive would not have stopped in time.