Inside a warehouse near the New Carrollton Station sits a prototype of Metro’s newest rail car, the 7000 series.

Constructed of plywood and painted gray, the prototype is half the size of an actual subway car, but it was made to give transit officials and riders a place to test designs for the interiors of the new additions to Metro’s fleet.

The new rail cars would bring some big aesthetic changes to the Metrorail system, retiring carpeted floors and orange and brown color schemes, while providing more interior signs, ample handholds and brighter lights. Although no final decisions have been made, officials presented feedback from focus groups to Metro’s board of directors during a committee meeting Thursday.

The Metropolitan Area Transit Authority plans to order 428 of the rail cars from Kawasaki at a cost of $886 million. The cars will be assembled in Lincoln, Neb., and are scheduled to be delivered by the end of 2013.

Three hundred of the new units will replace the oldest Metro rail cars, which date to the opening of the system 35 years ago and are known as the 1000 series. The National Transportation Safety Board has recommended that those be removed from service because of the damage they sustain in crashes.

The rest of the rail cars would operate on the new rail line to Dulles International Airport and Loudoun County.

Metro officials tested five interior designs with riders, train operators, advisory council members and people who have disabilities to get feedback on a range of options — including color schemes, flooring, and where to place handholds and other amenities.

Barbara Richardson, Metro’s assistant general manager for customer service, communications and marketing, gave The Washington Post a preview Wednesday of the 7000 series prototype. She has taken the lead in helping design the interior of the cars over the past six months.

“This is a chance to go from the drawing phase to a schematic, and it gives us a soft mock-up of what the car will look like,” Richardson said as she led the way up a set of stairs and into the rail car.

The 7000 series will feature:

l Brighter lighting. The new rail cars use LEDs instead of fluorescent lights.

l Twelve more seats in each set of four rail cars, compared with the 6000 series. Cab cars will have 62 vinyl padded seats; middle cars will have 64.

l New signs to identify the location of rail cars on a line.

The interior of the new rail cars has six new signs — two of which are digital “destination screens” that will track where the train is, where it is headed and the stations along the line. Four 24-inch-wide video screens will feature safety messages, ads, and information about parking at Metro garages and area attractions.

“We wanted the cars to be modern, futuristic,” Richardson said of the new signs. The digital screens that track where the train is along a line are meant to “give a sense of anticipation,” she said. “We want to have a feel of the train swooshing into the stations.”

l New hues. Metro said riders told them they preferred a color scheme of blues and light gray to create a “soothing, subtle, relaxing environment” on the train’s seats, flooring and walls.

l The elimination of poles that wheelchair users find difficult to navigate around.

l Privacy screens beside the priority seating near the doors, to give people their “own personal space,” Richardson said.

l Non-slip flooring instead of carpet.

l More handholds, including vertical bars attached to the back of every seat to “give people more places to hang on to,” Richardson said.

l Aisles that are two inches wider.

l Closed-circuit cameras.

Richardson said the newly designed rail cars will go through another round of feedback before the final details are sent to Kawasaki this summer.

“We’ll show people, ‘Here’s what you said. Here’s what we did.’ All the way until it goes to the manufacturer for production to start,” Richardson said. “We want to hear from people.”