MANSFIELD -- When software developer Krishna Valluru learns that his train home from Boston's South Station is running late, he calls home.

Nothing surprising in that, you say?

Not unless you consider that shortly after that call home, thousands of other rail commuters receive text messages or e-mails that the train is delayed.

Valluru and his family launched a free Web site in March that allows commuters to share news of MBTA train delays through their BlackBerrys, Palm Pilots, iPods and computers automatically -- and often before the T posts the schedule changes on its own site.

Commuters send e-mails or text messages about delays to Valluru's site, www.mytransitupdates.com, which then relays the information to other subscribers. Ultimately, the service may seek sponsors.

Valluru said the site, which is not affiliated with the MBTA, addresses a shared need: Commuters cannot adjust their personal or work schedules unless they check the MBTA Web site for delays.

`` Say we're at the station. The train is late. We can send updates to other commuters, so other commuters can get informed,'' Valluru said.

The MBTA sees the same need, spokesman Joe Pesaturo said.

The agency will roll out its own free instant transit update service this fall in response to commuter feedback.

`` If you can get information to someone's Palm Pilot or iPod while they're sitting at their desk in the financial district, you're getting them information before they've left the office,'' Pesaturo said.

`` If you check the Web sites for other major transit agencies comparable to Boston, you'll see that trend.''

Valluru does not consider the MBTA site a threat to his site, which has about 2,500 users.

He said commuters have told him they are unhappy with the MBTA. Valluru also contends his site will provide more timely information than the T.

`` Commuters are not going to call the MBTA. That is my advantage,'' Valluru said. Commuters subscribing to Valluru's service can get transit updates one day after completing an online member profile that includes their e-mail address and phone number.

Commuters then text message or e-mail the Web site when they spot transit delays. A toll-free number will be available by the end of July.

Valluru, his wife, brother and his sister-in-law take six-hour turns monitoring the site every day. They then disseminate the information.

Delays confirmed by the MBTA are distributed like this: `` Verified Info: Boston-Providence inbound running late by 30 minutes, updates will follow.''

Delays reported by commuters, but not confirmed, are distributed like this: `` Unverified Info: Boston-Providence inbound running late by 30 minutes, updates will follow.''

`` It's all public information that's out there,'' Valluru said. `` We are using public information that's available on their Web site and getting it out to commuters.

`` Most of the commuters say, `Thank you, very much.'''

But the MBTA says, `` Watch out!''

`` We don't have a problem with it,'' Pesaturo said. `` (But) our customers need to know that that information is not being provided by the MBTA. We can't be responsible for information found on that Web site.''

Valluru's site has not reduced the MBTA's Web traffic, either.

`` We get thousands of hits a day on our Web site. That has not changed,'' Pesaturo said.

What has changed, is how quickly commuters get transit delay updates.

Pesaturo and Valluru see an interest in instant notification beyond Boston.

Valluru plans to expand his service to New York this fall. He will hire someone to help run it.

`` First, we are planning to make sure the Boston users are happy,'' Valluru said.

MICHAEL GELBWASSER can be reached at 508-236-0372 or at mgelbwasser@thesunchronicle.com.