Amtran is planning to construct an auxiliary garage across Fifth Avenue from its headquarters building to store vehicles and equipment for which it no longer has enough room indoors, because the new compressed natural gas buses are five feet longer than the old buses.

The 4,800-square-foot auxiliary garage will be without “frills” but could cost about $1 million — money which PennDOT has indicated it will grant, according to Amtran General Manager Eric Wolf.

Currently, 16 buses are CNGs, with seven more slated to replace diesels in 2021 and — based on information learned recently from PennDOT — three more to complete the transition in 2024, according to Wolf.

The proposed garage would hold a dump truck equipped with a plow and a trailer that carries a mini-loader; a service pickup equipped with a plow; two sport utility vehicles, a minivan and a sedan used for shuttling drivers and by management and pallet racks for equipment and supplies, Wolf said.

So far, the longer buses have relegated the SUVs, the minivan and sedan to outside storage, according to Wolf.

After the seven additional CNGs arrive in 2021, three or four buses would need to be stored outside, if there is no auxiliary garage by then, he said.

Even more buses would need to be stored outside starting in 2024, without the auxiliary garage.

Storing buses outside is problematic, according to Wolf.

“Picture today,” he said Wednesday — a day when several inches of snow fell, followed by freezing rain. “How do you clear the snow or ice?”

Inside, the snow and ice simply melt, he said.

If Amtran can keep the auxiliary garage at fewer than 5,000 square feet, the state’s Unified Building Code won’t require a sprinkler system, according to consulting landscape architect Brent Cartwright of EADS.

Because Amtran’s headquarters building is right across Fifth Avenue, the auxiliary garage won’t need restrooms, Wolf said.

There will be a heating system, but it will be just sufficient to keep things from freezing and relatively dry, Wolf said.

The auxiliary garage would be steel-framed, with brick accents, so it fits with the look of the Amtran complex, which comprises the headquarters building — which consists of the maintenance and storage garage and administrative offices — the Trolleyworks building, with a conference room and two rental suites; and the Battery Barn, whose tenant is a fitness center.

The auxiliary garage could be made to look like a garage that once stood approximately on the present site of Family Video, when Amtran predecessor Altoona & Logan Valley Electric Railway was in operation, according to board Chairman Scott Cessna, who showed a picture of the old garage about the time of A&LVERy’s last trolley run.

It might make sense to transfer the A&LVERy sign that once hung on that old garage and now adorns the maintenance building to the new garage, Cartwright said.

The auxiliary garage would be located across a small parking lot on the Logan Boulevard side of the Trolleyworks building, according to Cartwright.

Amtran is making the transition to CNG as part of a statewide PennDOT program designed to encourage the use of natural gas extracted in Pennsylvania.

PennDOT will probably cover the entire cost of the final three CNG buses that could be delivered in 2024, Wolf said.

PennDOT and the Federal Transit Admini­stration will share the cost of the seven CNGs slated to arrive in 2021.