Due to a "system-wide signal interruption," according to a Caltrain spokeswoman Christine Dun, service has come to a standstill. It has something or other to do with a "computer malfunction in the main signal operating system in the San Jose yard." SFist readers have also told us that they're stuck at Bayshore. It is not yet known just when service will be fully restored. In related news, there was a "stage 3 at central," whatever that means, on Bart that resulted in a train getting stuck under the bay. Bart service, though, seems to be running as usual now.