Transit Operations and Service Delivery
What this domain tests
Transit Operations and Service Delivery tests how schedules become reliable service: headway, cycle time, blocking, recovery time, on-time performance, deadheading, and productivity. Expect calculation items and scenario items about restoring service.
Core rules and concepts
- Frequency is trips per hour; span is hours of service. A high-frequency route can still have poor reliability.
- Cycle time = round-trip running time + layover and recovery. Vehicles required = cycle time ÷ headway, rounded up, plus spares.
- Platform hours include deadhead; revenue hours do not. Budget and productivity measures must use the right denominator.
- On-time performance uses a defined tolerance, often not earlier than 1 minute and not later than 5 minutes, measured against the schedule.
- Blocking links trips into a vehicle day; interlining can reduce deadhead but spreads delay.
Worked example
A route has a 72-minute round trip and 18 minutes of recovery, so cycle time is 90 minutes. At a 15-minute peak headway, vehicles = 90 ÷ 15 = 6. A 20% spare ratio requires 7.2, rounded up to 8 vehicles. If peak running time rises to 80 minutes, cycle time becomes 98 and vehicles = 6.53, rounded to 7, plus spares.
Traps that cost marks
Forgetting recovery time; computing vehicles from one-way running time; using revenue hours when the question asks platform hours; and comparing on-time performance across routes with different tolerances.