"Scuba mask" is the nickname of the former T 478.3 (750/753) series diesel locomotives built from 1970 by CKD in Praha. 757.015, reflected in a puddle on the platform of Zvolen station, is a largely rebuilt locomotive with new Caterpillar 3512 CHD, 1550 KW prime mover, done by ZOS Zvolen in june 2014. In Slovakia this diesel locomotives are called "Okuliarnik".