SEATTLE (Reuters) - Three of the largest engine makers face a Wednesday deadline to provide Boeing Co BA.N with formal proposals for how they would power the planemaker's possible new mid-market jet, an aviation magazine reported.

FILE PHOTO: A Boeing logo is pictured during the European Business Aviation Convention & Exhibition (EBACE) at Geneva Airport, Switzerland May 28, 2018. REUTERS/Denis Balibouse/File Photo

A Boeing spokesman declined to comment but said the Chicago-based planemaker continues “to make good progress” in developing the jetliner’s “business case.”

Boeing’s request for proposals would mark an important step toward bringing into service a jet with the potential to carve out new routes in 2025, though Boeing has stressed it would not be rushed into a decision on the plane.

CFM International - a joint venture between General Electric GE.N and Safran SAF.PA - Pratt & Whitney UTX.N, and Rolls-Royce RR.L were submitting proposals, the Air Current reported, citing unnamed sources.

Boeing is studying plans for what industry sources describe as a hybrid jet combining a wide cabin and a restricted cargo space, moulded to fly efficiently in a space between the industry’s single-aisle jets and wide-body long-haul aircraft.

Boeing aims to broadly replace its 757 model, a narrow-body jet with a single aisle. It envisions a mid-market jetliner with 220 to 270 seats and a range of up to 5,000 nautical miles, with global demand for 4,000 to 5,000 jets over 20 years, though rival Airbus AIR.PA disagrees with that forecast.

Boeing wants an engine that burns 25 percent less fuel for every pound of thrust it produces compared with the 757’s decades-old turbines, the Air Current reported. The timing for choosing either one or two manufacturers was not immediately clear, it said.

General Electric GE.N did not immediately respond to a request for comment. Rolls-Royce, which is facing problems with parts of the Trent 1000 engine that have led to the grounding of some 787s for repairs, said, "whenever an aircraft manufacturer comes forward with a proposal we will have a technology response."

A Pratt & Whitney UTX.N representative referred to comments made earlier this month by its commercial engine business chief Chris Calio: "I think the (Geared Turbofan engine) scales well, and so we're always looking and interested in other applications for the GTF as long as it makes sense for us."

Jefferies analyst Sandy Morris said in a research note that CFM “is likely to be the keenest contender”, and might offer a derivative of its GE9X engine, which serves the forthcoming 777X. He said he would be surprised if Pratt and Rolls were not also in the mix.