Railways Abbreviations and Acronyms
- NWZNorth West Zone
- OCCOccupied
- OCLOperational Communications Link
- OCSOnegcontrol Switch
- OCUOperator’s Controk Unit
- OEOperating Expenditure
- OETROutline Engineering Train Requirements
- OFNOptical Fibre Network
- OHLOverhead Line
- OHNSOverhead Line Neutral Section
- OLBIOff-Line Battery Inverter
- OLEAROverhead Line Equipment Asset Register
- OLEMIOverhead Line Equipment Master Index
- OOROut of Round
- OPEXOperating Expenditure
- OPMOperational Planning Manager
- OPUGOther Passengtr Upgrades
- ORNOverlay Radio Network
- OSGOperation Safety Group
- OSGROrdnance Survey Grid Reference
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