Queueing Theory: Faster Trains Might Make London Underground Slower

Let's take a look at a great real-world example that effectively illustrates how queuing theory can be unintuitive even in situations that seem simple. A recent BBC report reveals researchers’ suspicions that trains in the London Underground may be moving too fast, causing the entire system to be under-optimized, due to certain hubs in the system where it’s more likely for bottlenecks to form, due to riders making transfers.

“Reporting their findings in the journal Royal Society Interface, the researchers calculate that London’s system would function best with underground trains travelling about 1.2 times faster than the average speed on the roads. This makes the optimum Tube speed approximately 13mph (21km/h); the current average is 21mph (33km/h).”

Trains going too fast means that the whole Underground system goes more slowly? The magic of queuing theory! Check out the full BBC article here. Queuing theory can be fascinating for all the extra intricacies it reveals within a system. Even simple problems might be more complex than you suspect, and you can find applications for the theory all through daily life.