Manually Controlled Barrier crossings — MCBs — are what happen when a crossing is too busy or too important to be left to automation alone. A real person operates them, usually from a signal box, and the barriers go all the way across the road.
How MCBs Differ from AHBs
The key differences:
- Full barriers — MCBs have barriers that cover the entire width of the road, both sides. No gaps. Once they're down, you're not going anywhere.
- Human operated — A signaller monitors the crossing via CCTV or direct line of sight and controls the barriers. They won't raise them until they've confirmed the crossing is clear.
- Longer warning time — Because a human is in the loop, the sequence from first warning to barriers down tends to be longer and more deliberate.
The MCB Sequence
- Road traffic lights change — Red lights and sometimes an audible alarm warn road users.
- Full barriers descend — All four barriers (or two full-width barriers) close across the road.
- Signaller confirms — The signaller checks the crossing is clear and gives the signal for the train to proceed.
- Train passes — Through it goes.
- Signaller raises barriers — Only when satisfied the train has fully cleared the crossing.
Why the Inspector Rates MCBs Highly
MCBs tend to score well in the Action category because:
- Full barriers are more dramatic than half barriers
- The barrier mechanism is often more substantial and visually impressive
- There's usually more infrastructure to observe — signal box, CCTV cameras, telephones
- The full closure creates a more complete "event" feeling
Where to Find MCBs
MCBs are typically found at:
- Busy road junctions where an AHB would cause too much risk
- Town centres where the road carries heavy traffic
- Locations where the sighting distance is poor for approaching drivers
- Near stations where trains might be stopped or slow-moving
The Future of MCBs
Network Rail has been gradually converting MCBs to obstacle detection systems and CCTV-monitored crossings, reducing the need for staffed signal boxes. This means some classic MCBs with their traditional signal boxes are being lost. Another reason to visit them while you can.