It would mean dozens of extra passengers would be able to fit onto services.
London Midland's chief executive Patrick Verwer revealed the plans during a public drop-in session at the Tesco store in Hednesford.
He said: "We are looking at having longer trains with more carriages.
"By increasing the number of seats, we will be increasing demand and attracting more passengers."
He was not able to say exactly how many extra seats would be on trains if extra carriages are added but said the move would mean station platforms would need to be extended.
It is hoped the speed on the Chase Line, which runs between Walsall and Rugeley, will increase to 75mph from 45mph when the electrification project is complete.
Centro's rail partnership manager Steve Fisher said increasing the speed will 'shave minutes' off journeys and allow for extra services to be introduced.
He also said a direct service from Cannock to London could be introduced in the future.
He added: "Services from Walsall to Rugeley are currently every hour. One thing we would like to see is increasing that service to every half hour.
"The speed on the line is currently 45mph. We want to increase it to 75mph. It will shave minutes off journey times."
The overall £30 million electrification scheme is due to be completed in three years.
It will see the installation of 15 miles of overhead cables. Diesel trains will also be replaced by electric ones. A number of bridges along the route will be rebuilt or modified as part of the project.
The bridge in Station Road, Hednesford reopened on Thursday. Around £1.1m was spent rebuilding the structure.
Rail bosses have promised long-term benefits of electrification such as boosting capacity, reducing carbon emissions and cutting the cost of running the railway. They hope it will also encourage more passengers onto trains.
As well as increasing the speed of the trains, the improvements will also see the introduction of automatic ticket machines at stations and the upgrade of sleepers, rails and platforms.
The event at Tesco was organised by Cannock Chase MP Aidan Burley. He said it was useful meeting members of the public and answering questions and concerns.
The Chase Line runs through Hednesford, Cannock, Landywood and Bloxwich.
Gavin Williamson, MP for South Staffordshire, has campaigned to limit the speed of trains through Great Wyrley and Cheslyn Hay when the line is complete.
He has written to transport secretary Patrick McLoughlin, requesting confirmation that trains travelling through these areas will not exceed a speed of 45mph.
He has also requested that environmental mitigation measures be put in place to reduce the potential impact of the electrification on residents in South Staffordshire.