Jennie Reed, left, and Lauren Tamayo of the U.S. cycling team take an escalator out of London’s subway after taking a silver medal. Olympic athletes rode ‘the Tube,’ which uses Cubic Corp. mass transit ticketing systems.

Jennie Reed, left, and Lauren Tamayo of the U.S. cycling team take an escalator out of London’s subway after taking a silver medal. Olympic athletes rode ‘the Tube,’ which uses Cubic Corp. mass transit ticketing systems.

The people staging the Summer Olympics in London worried about everything from terrorism to bad weather to a mass transit meltdown...