The encyclopedia · Engineering & Operations · Operational decision · 2014–2017
GE and Norfolk Southern dispatch thousands of trains in real time
Norfolk Southern's dispatchers handled trains one at a time; an optimizer with GE plans all movements, lifting speed over 10% and saving hundreds of millions.
Norfolk Southern · General Electric
the move
Norfolk Southern runs a large rail network and its dispatchers had to decide, minute by minute, where trains should meet and pass, each decision local and easily conflicting with the next.
The naive approach is to rely on dispatcher experience and local rules, accepting that trains wait and average speed suffers.
The move was an optimization algorithm-based system, called Movement Planner, that computes an improved plan for thousands of trains in real time.
It increased average line speed by more than 10% and saves the railroad in the hundreds of millions a year; Norfolk Southern notes that each one mile-per-hour of average speed is worth roughly $200M a year in capital and operating expense.
why it works
- Individual dispatcher decisions fight each other, while a network-wide plan removes the conflict.
- Faster average speed avoids the need to buy more track and locomotives.
- Real-time replanning handles constant perturbations and disruptions.
- The value is large and measurable: speed is money on a railroad.
what transfers
A network run by many local optimizers leaves money on the table. Plan all movements together against the schedule and you raise throughput without spending on extra track.
what came after
Norfolk Southern adopted Movement Planner as a core dispatch tool and modernized its operations; INFORMS named it a finalist for the 2017 Edelman Award for the work with GE.
references
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