A majority of residents want to see significant improvements to the commuter rail system, but they also believe the costs should not be passed along to riders in the form of higher fares or an increased gas tax, according to a new poll.

Proposals such as a North-South Rail Link, the South Coast Rail project, and extending the commuter rail west to Springfield and Pittsfield all saw support of 75 percent or more in a MassINC poll of 1,430 Massachusetts residents published Thursday.

The most popular among those was replacing the existing diesel fleet with electric trains: 84 percent of residents polled said they strongly or somewhat support the idea, which is included in a handful of options an MBTA panel is exploring for the future of the commuter rail system.

Most respondents also saw benefits in a regional rail system, where trains run more frequently in both directions and are focused less on rush hours into and out of Boston. More than 80 percent said such an upgrade could increase ridership, decrease traffic and boost economic development across the state.

But electrification and transition toward a regional system will be expensive. The Rail Vision Advisory Committee, which is studying several long-term commuter rail development options, estimated in July that doing both could carry $23.6 billion in capital costs in 2020 dollars and would increase annual operations and maintenance costs by $823 million.

A majority of residents polled by MassINC expressed support for generating revenue through mechanisms targeting the wealthy or developers, but opposed income sources likely to affect most commuters.

Sixty-seven percent said they do not agree with increasing commuter rail fares to generate additional funding for regional rail and 64 percent opposed higher parking fees. In fact, 87 percent supported lowering fares and 80 percent said it would be worthwhile to offer discounts to low-income riders.

Charging roadway tolls to get into Boston at peak times, similar to a congestion pricing system long suggested by transportation reform advocates, saw 58 percent opposition compared to only 34 percent support among poll respondents.

One idea that Beacon Hill leaders have floated as a possible topic during a forthcoming House debate on transportation revenue this fall is increasing the state’s gas tax, which was last raised in 2013. A 2013 law indexed it to inflation, but voters repealed that language just one year later.

Even a simple increase to the gas tax remains unpopular among residents surveyed for Thursday’s poll: 68 percent said they oppose the idea and only 26 percent said they support it.

However, several other revenue sources state leaders are pursuing were popular in the poll. Sixty-one percent of those surveyed said they support a 4 percent surtax on household income over $1 million, the subject of a proposed constitutional amendment that would direct the new money toward transportation and education.

Seventy-one percent also backed charging fees to real estate developers who pursue projects near rail stations, and 67 percent supported using revenue from the still-in-development Transportation Climate Initiative, a multi-state compact aiming to reduce carbon emissions through a cap-and-invest program, on regional rail.

Scrutiny has been high on both the legislature and the Baker administration this summer in the wake of a Red Line derailment that caused more than three months of service disruptions and the administration’s congestion study that warned traffic has reached a “tipping point.”

In Thursday’s poll, 64 percent of residents said they had a very or somewhat favorable opinion of Gov. Charlie Baker, while 49 percent strongly or somewhat approved of how he is handling the state’s transportation needs.