A free downtown trolley is a romantic idea and a seemingly practical one, but one that has been found unsustainable. When METRO began charging a 50 cent fare for trolley rides in 2004, the death knell was sounded: The line closed in 2005, and with it, the affordability and convenience of cool public transportation in downtown Houston.

But that's all changed this week with a partnership between the Houston Downtown Management District, the BG Group and Houston First Corporation reprising that hop-on-hop-off transportation with METRO-operated Greenlink.

The 18-stop, 2.5 mile circular route through downtown connects cultural centers and tourist destinations, METRO transit hubs and entertainment, to provide Houstonians and visitors with free and easy transit between the hours of 6:30 a.m. and 6:30 p.m.

CultureMap experimented with the Greenlink during the lunch hour on Wednesday to see what riders have in store.

After a wait time of less than two minutes at stop No. 1 (on the corner of Smith Street and McKinney Street), I found myself on a powerfully air conditioned bus, smelling strongly of brand new upholstery.

Two other passengers — a businessman carrying a FedEx package, and an older gentleman wearing a baseball cap — shared the 20-something-seat cabin, but alighted, separately, just a few stops later.

I continued the route alone until the corner of Dallas Street and La Branch Street, then stepped off and walked the block to Phoenicia Downtown Market for a cold drink.

I met the Greenline again near the intersection of Caroline Street and Walker Street — this time waiting an agonizing seven minutes and 19 seconds for the approach of the bus (the average time wait time during peak periods is between seven and 10 minutes) — and continued the circuit back to the beginning.

The bus was more full of curious first-time riders on the final leg, with a group of coworkers in business attire and a young family in summer gear, all reading a complimentary Greenlink brochure, discussing rules (no eating or drinking on the bus) and destinations (from the theater district to the George R. Brown and a number of spots in between).

We all disembarked at City Hall, me to wrap up my experiment, and the others to check out the food stalls at the weekly farmer's market.

I listened to the hum of the Compressed Natural Gas-powered bus as it drove away, eyeing its endearingly boxy, bulbous form as pedestrians scrambled past on the sidewalk, sweating through ironed shirts.

Forget convenience and connectivity: This is why the Greenlink is crucial for downtown Houston.

Find more information about how to ride at www.downtownhouston.org.