Western Cullen Hayes AAMBF is designed to be used with Western-Cullen-Hayes Model HB or HBXS sliding derails. When the derail is placed in the derailing position, the AAMBF raises to provide Blue Signal protection in compliance with FRA and OSHA requirements. The AAMBF incorporates a gear reduction box and a 360 degree articulating sign shaft for smooth operation, reducing damage to the unit if accidentally struck by rolling stock.