ScotRail is seeking views about whether firms should be approached to provide products, which could include toiletry brands like soaps, in on-board loos.
Companies could also be invited to advertise on the outside of carriages.
The plans are revealed in new customer research being undertaken by Scotland’s main train operator for its future fleets.
Members of the firm’s 7,000-strong online customer panel are being asked: “How would you feel about ScotRail allowing another brand to sponsor part of the train?
"For example, sponsoring the exterior of the train, or using their products and logos inside the toilet on board.”
Researchers also want to know whether passengers would like to see some seats removed to provide more space, including around the doors for people standing.
That could mean reducing the three seats on one side of the aisle to two on some trains.
Views are also being sought on whether floor-to-ceiling luggage racks should be added in addition to overhead racks, which would also mean the loss of seats.
Other questions include whether passengers are happy with half-size tables or would like to see full tables between seats.
ScotRail said the poll was to plan the interiors of new trains to run on routes in and around Glasgow, which carry around two thirds of its passengers.
It said: ”We will be replacing 70 per cent of our train fleet over the next 15 years due to our de-carbonisation policy and the life expiry of rolling stock.
"Consulting customers is an obvious first step as we develop requirements for the new fleets.
“The interior design and layout of our train carriages is a common theme in our market research and we regularly capture our customers views about the experience they have on board our trains.
“ScotRail is continually researching all aspects of the railway, including any potential new revenue streams, in order to enhance the service our customers receive and we will continue to do this in the future.
“All opportunities will be looked at.”
However, a brand consultant said ScotRail might struggle to find a company willing to stock its products in train toilets.
They said: "I would find it very difficult to think of appropriate brands to approach.
"It would need to be a company whose products had mass appeal that would be comfortable with that."
The consultant said passengers would be more concerned about the basics: "Probably what people want most is that the toilets are clean, the door will stay locked and they have the amenities you would expect – soap, toilet paper and a dryer.”
They also questioned the attraction of carriage exteriors to advertisers because of their low visibility, as trains travelled fast and did not stop for long at stations.
By contrast, Edinburgh’s trams have been sponsored by firms such as glazier CR Smith.
The consultant said: "Trains are different from taxis, buses or trams in a city centre, where you’ve got a lot of people and these vehicles are stopping and being seen.
"I would wonder if a brand would view trains as being of huge value, other than in the context of providing a better experience, such as from an environmental perspective.”