The 4-pole NFZB auxiliary contactors meet the latest standards for rolling railway vehicles and enable installation in passenger or driver's cabs of trains that frequently travel in tunnels or underpasses. They are used to switch auxiliary and control circuits. They meet all important standards for rolling stock: IEC 60947-4-1, IEC 60947-5-1, IEC 60077-1/-2 and applicable parts of the EN 50155 standards, shock and vibration resistance according to IEC 61373 Cat. 1, Class B. They also achieve the highest levels of fire and smoke behavior while complying with the European standard EN 45545-2 (HL2 hazard levels) when mounted in groups. The auxiliary contactors enable direct control via =24V DC 500mA PLC outputs and require a very low holding power of just 1.7W. NFZB auxiliary contactors can withstand short voltage dips and voltage drops (according to SEMI F47-0706) between 24...250 V 50/60 Hz. They have built-in overvoltage protection and do not require additional suppression elements.