Train Numbering:
 

1xx	Red Line - Shady Grove-Glenmont Trains
2xx	Red Line - Grosvenor-Silver Spring ("Downtown") Trains
3xx	Yellow Line
4xx	Blue Line
5xx	Green Line
6xx	Yellow Line
7xx	Non-Revenue
8xx	Orange Line
9xx	Orange Line

Rail Personnel:

• ATC xxx - Automated Train Control
• Car Equipment xx - Train Car Maintenance
• PM xx - Preventive Maintenance (track)
• Unit xx - Rail Supervisors

Metro Event Codes:

• amber-amber - fire
• grey-grey - smoke
• lemon-lemon - crowd control
• purple-purple - jumper or person on tracks
• tan-tan - bomb threat
• white-white - hostage situation
• silver-silver - summon police
• black-black - train collision or derailment

Railroad Terminology Used By Metro:

• Absolute Block - portion of track which only one train is allowed at a time
• Absolute Permissive Block (APB) - portion of track within which train movements are controlled by signals, whose indications supersede the superiority of trains
• ATO - Automated Train Operation
• Block - portion of track controlled by signals
• Crossover - connection between two adjacent tracks
• Hand Brake - manually operated brake used to hold cars from moving
• Interlocking - interconnected signals that must operate in proper sequence
• Lunar - white light signal
• Mode 2, Level 1 - manual train operation
• Restricted Speed - a speed that will permit stopping within one half the range of vision; short of train, engine, railroad car, stop signal, derail or switch not properly lined, looking out for broken rail, not exceeding 20 MPH
• Yard - a system of tracks, other than main tracks and sidings, used for making up trains, storing of cars and for other purposes