“Today is my second time taking the 504 Express bus, and it’s been a great experience, since I can get to work fast,” said Katelyn Boller, a 30-year-old product manager. “I like how there are only three stops because it makes the ride go by quicker.”

The 502 Express to Copley Square pulled into Watertown Yard shortly after 8 a.m. and filled up quickly. Then came the 57 bus to Kenmore Station, followed by the 504 Express to downtown Boston.

Early Monday morning, temperatures were climbing toward the 90s when a small crowd gathered just outside Watertown Square to board an air-conditioned MBTA bus to Boston.


While no commute is perfect — other bus routes in Watertown are plagued by traffic and overcrowding — the 504 Express is more comfortable and dependable than many other modes of transportation.

After leaving Watertown, the 504 picks up riders in Newton Corner before heading into Boston via the Massachusetts Turnpike. Passengers are dropped off in Boston at the intersections of Lincoln and Beach streets and Federal and Franklin streets. (The bus also stops at Stuart and Dartmouth streets between 9:20 a.m. and 4 p.m.)

Rebecca Cinci, 42, a compliance analyst for a Boston company, said the inbound commute is better than the ride home.

“It’s reliable in the mornings, but definitely not in the afternoon,” she said as she waited to board in Watertown. “If you’re trying to follow a strict time in the afternoon, it’s a loss, since there’s a lot of traffic.”

But then Cinci compared it to the Green Line, the beleaguered trolley route that passes through Newton Centre about four miles to the south. As temperatures soared Monday morning, Green Line passengers became stuck on packed trolley cars for nearly an hour because of power issues.


On the 504 Express, Cinci said, “at least I know that I’ll always have a seat and it’ll be a quiet ride, both of which I never had when I took the Green Line. So it’s worth it for me.”

Buses provide the only public transportation in Watertown, which, unlike surrounding cities and towns, lacks commuter rail and trolley service.

Ridership varies widely among the eight bus lines that serve Watertown. The busiest is the 57 bus, from Watertown Yard to Kenmore Station. Average weekday boardings in both directions totaled 10,367 passengers, compared with just 1,482 passengers for the 504 Express, according to 2014 ridership data in a recent report by the state Department of Transportation.

David Chez, a 34-year-old Watertown resident, said he has no complaints about the 504 Express.

“Overall I love it,” he said. “I’m a software engineer, and the bus drops me off right in front of my work building, so it’s incredibly convenient.”

After one 504 Express left Watertown Yard at 8:47 a.m., the fullest it got was 25 people — there were seats still available, the air conditioning was comfortable, and the ambience was relaxing, with hardly any noise except from the bus itself.

It reached its final destination in downtown Boston at 9:20 a.m.

For an early-morning commute, it was a swell ride.

Rebecca Bicalho can be reached at rebecca.bicalho@globe.com.