Greater Bangkok Commuter rail is a commuter rail system in Bangkok Metropolitan Region, Phra Nakhon Si Ayutthaya Province, Saraburi Province, Lopburi Province, Suphan Buri Province, Ratchaburi Province, Chacheongsao Province, Nakhon Nayok Province, Prachinburi Province, and Samut Songkhram Province. It runs from and to the outskirts of the city during the rush hour, and passenger numbers have high. It is operated by State Railway of Thailand (SRT) that also operates inter-city rail. Commuter rail services always have number 3xx. Most of the system are double track.