139 USSD: It means Unstructured Sequential Supplementary Data.

The communication held in this mode is based on sessions and is interactive. The customer dial *139# from any operator hand held device. The display message shows- Welcome to Railway Enquiry Service

Following Rail enquiry services are displayed immediately:

1. PNR Enquiry
2. Arr/ Dep Enquiry
3. Seat Availability
4. Fare Enquiry
5. Train Name/ No. Enquiry
6. Train Time Table
7. Locate Train

The customer presses the desired menu button and receives all the information via response display message on screen and a SMS.