Fortunately, it seems like the police actually have better ideas than patrolling trains with arms. The Standard article, concluded by pointing out that a police source said "We do want to maintain an increased presence and vigilance around the transport network and sustain the present level for some time to come."
A greater emphasis is being placed on hidden tactics to disrupt "hostile surveillance" by terrorists on the Tube network. More people are being brought in to monitor CCTV cameras at key stations and more covert officers will work with the CCTV watchers on the ground. "We want to try to pick up people planning an attack before they do it," a source said.