NIGHT AFTER NIGHT for weeks, Ada Williams of Mayfair ended her SEPTA shift at 2:10 a.m., pulled her bus into the Frankford Terminal, then spent hours turning a special "Happy Holidays" bus into a winter wonderland on wheels.

Day after day, Williams' co-worker Dennies Scott of Mayfair did the same.

The yuletide-fueled holiday bus - swaddled in candy-cane stripes on the outside, sparkling with ornaments and glitter wrap on the inside - has been carrying city riders to work and shopping since the day after Thanksgiving.

At a Frankford Terminal holiday party, Williams and Scott boarded the bus they've made over and saw that it was good.

Scott was decked out in the green elf costume, trimmed in red, that she's been wearing lately on her regular bus routes.

Williams said she, too, was an elf in spirit. "But I can't wear that elf outfit," she said, smiling at Scott. "I'm too chunky."

"You are not!" Scott said, widening her eyes for emphasis.

"I wore my red shirt instead," Williams said, adding that she'd spent so much spare time working on the holiday bus that she hadn't readied her home for Christmas.

"My decorations are still in the bag!" she said, laughing. "I usually hang garland all the way down the stairs and around the doorway. Not this year. Not yet."

But she and Scott did hang garland all the way around the bus ceiling, along with dozens of dangling, dazzling Christmas ornaments. They even gift-wrapped the fare box in metallic green.

"We're awesome, of course," Scott said, laughing, "but it wasn't just us girls."

The holiday bus, she said, was a rare chance to work with the maintenance mechanics.

"Usually, we pass by their workshop, say, 'Hello,' and that's about it," Scott said.

Not exactly, said Joe Vozzelli, a SEPTA mechanic for 30 years. "They're always angry at us," he said drily.

Williams confessed. "We shout at them, 'This door's not working!' Stuff like that," she said.

"They're a necessary evil," Vozzelli deadpanned. "Without them, we wouldn't have a job."

Fred Eisenhart, Vozzelli's fellow mechanic, wrapped the bus in red-and-white stripes, applying each stripe individually with painstaking care.

Other mechanics pulled out each passenger window and installed a clear "vandal shield" to protect the big candy-cane decals that Scott and Williams applied.

Eric Trespalacios, a SEPTA air-conditioning specialist for 20 years, hand-stenciled giant snowflakes on the wheelchair lift, painted the lug nuts on the bus' wheels red and green, and hand-lettered "Seasons Greetings from Our Family to Yours" on the rear window.

At the party, the holiday bus was jammed with new toys collected during SEPTA's Yule Toy campaign.

But when the bus gets rolling on routes all over Philly today, the toys will be at SEPTA headquarters on Market Street near 12th, being sorted for delivery by Christmas Eve to agencies that serve children.

Williams has seen the holiday bus work its magic on kids and adults alike.

"Some grown-ups get on the bus, and you can see they are sort of down," she said. "Then they notice all the decorations and you see the change in their faces. To know I'm a part of that, well, it's a once-in-a-lifetime experience."

Scott just nodded - and smiled.

On Twitter: @DanGeringer