The proposed new Metro station look. (Courtesy of WMATA/COURTESY OF WMATA)

The iconic design of Metro’s rail stations, intended to echo the monuments that make up the capital landscape, is going to be given a very modern makeover, officials said Thursday.

Stainless steel, bright lights and clear glass would supplant the soft lighting and dark colors that were defining elements of the subway system when it was designed and built in the 1960s and 1970s.

The proposed changes, which would be most noticeable in some of the system’s underground stations, mark a striking departure for Metro. And just as the system’s original design was the subject of great debate, the transit agency’s announcement is already eliciting pointed critiques from some quarters.

The bustling Bethesda station will be the prototype for the redesigned look, and Metro said it will cost about $10 million to roll out the features there by mid-2015.

“This embodies all the elements that our customers have been clamoring for,” Metro General Manager Richard Sarles said of the new look. “We are preserving the great arched spaces that make Metro unique while updating certain elements from the outdated ’70s brown look that was common at the time in favor of an updated, 21st-century look.”

Carrying out the modernization effort across much or all of Metro’s 86-station system could cost tens of millions of dollars, said Dan Stessel, a Metro spokesman. He said that after completing the Bethesda prototype, the transit agency will decide how to move forward.

Already, the agency is in the throes of an expensive and disruptive effort to reconstruct its long-neglected rail infrastructure, and this year, Metro outlined a multibillion-dollar plan to expand the system over the next few decades.

The announcement is sure to stir some of the transit agency’s critics, who are likely to say the rail system’s performance, not its aesthetics, should be the focus. But historic preservationists and transit historians have their own critiques, saying the new design will compromise the distinctive design that emerged from years of debate over what a subway system for the nation’s capital should look like.

Metro’s designers used concrete, granite and bronze in designing the stations because the materials evoked the grandeur of the capital city’s monuments and gave Metro an appearance that was unique among the nation’s subway systems.

“Every generation has the impulse to make it brighter, but that’s like taking a Victorian storefront and slapping aluminum siding on it,” said Robert Bruegmann, the author of a book on Metro’s principal architect, Harry Weese.

Like any major project in the nation’s capital, a change to the stations will probably create a debate. Just changing the names at a handful of Metro stations took several months and involved the transit agency’s board members, community groups, universities, hospitals and others.

Thomas Luebke, secretary for the U.S. Commission of Fine Arts, said his agency would expect the changes to stations to be presented to the commission, which was heavily involved in Metro’s original planning and design.

In the decades since, the transit agency has regularly presented the commission with plans to add escalator canopies, increase lighting, install art and change signs, Luebke said.

“We treat Metro as common space,” he said. “We would expect changes to be presented to us.”

The National Capital Planning Commission, which was heavily involved in refining Metro’s original designs and plans, said the agency does not foresee a “review role” for itself in the new station design.

“Those look like primarily interior station changes,” Julia Koster, a planning commission spokeswoman, said after reviewing a Metro-supplied video of the makeover. “Typically, our review is for location and external changes.”

Stessel said the agency’s in-house architects came up with the new station look for the Bethesda prototype. He also said Metro plans to “engage and consult” with the fine arts and capital planning commissions.

Metro officials said they chose Bethesda as the pilot for the makeover because the station’s three escalators are scheduled to be replaced early next year. Another reason is because the current design of the station limits the ability to add lighting.

Metro’s video of the station makeover shows more lighting in stations and around signs on platforms. Sarles said that stations will be “much brighter,” allowing riders to “make it through stations more easily.”

“It will just feel good,” he said.

Concrete walls around stairwells would be replaced with glass and steel. New lighting would be installed along escalators. Station managers would have smaller kiosks with digital panels to give train information. Anti-slip flooring would be put in near escalators.

“Customers may notice that Metro brown has been replaced by stainless steel and light gray to create a lighter, more modern appearance,” Metro spokeswoman Caroline Lukas says in the video.

The tall, brown posts that show station names on platforms would be replaced with more directional signs for passengers that would be higher up, “making it easier to see and reducing clutter,” according to the video. Some of the posts would also have digital signs providing train arrival information.

But Bruegmann said the new directional signs looked like something “in a shopping center” and not distinguished enough for the nation’s subway system.

“You can’t be too careful,” he said, in making changes to the look of Metro. “We’re talking about [changes] to the greatest public space in the nation’s capital.”

Zachary M. Schrag, author of “The Great Society Subway” — a history of Metro — agreed.

“Weese was very consistent on the palette of materials he was going to use,” he said. “That meant granite, concrete and bronze with some glass, so putting in a lot of stainless steel strikes me as a pretty significant departure from Metro’s design.

“I would describe it as a sacrifice of an important work of 20th-century architecture.”

Many of Metro’s rail stations have dim and, in some cases, dark parts. Riders have raised concerns that lighting has been a low priority while the agency has pushed aggressively to do major track rebuilding in the past few years.

This year, Metro rolled out a long-range plan to deal with the projected increase in riders on the already-crowded system. The plan, dubbed “Momentum,” calls for building a tunnel downtown and another under the Potomac River, projects that would require billions of dollars.