The MBTA yesterday took a major step toward procuring 75 Commuter Rail coaches that could be online by fall 2012. The bilevel coaches will be the commuter rail’s first new cars in five years and will allow numerous 20- to 30-year-old coaches to be retired.

The coaches, which feature improved rest rooms, Wi-Fi, tables and real-time LED message signs, will mostly benefit North Shore customers.

Mock-ups of the new coaches are open to the public starting at 3 p.m. on Friday through Nov. 5 at North Station.

The MBTA started working on the customized coaches, which on average cost $2.3 million, with contractor Hyundai-Rotem in 2008.

“Part of the design process is the creation of these mock-ups,” MBTA Director of Vehicle Engineering Jeff Gonneville said. “It gives us an opportunity to see the items and designs we’ve been working with on paper up to this point.”

The T expects four test coaches to be delivered next fall.