NEW YORK (CBSNewYork) – The long-awaited L train slowdown is now underway.

While it’s not a full shutdown, train service has been drastically reduced on nights and weekends.

The slowdown follows years of debate and planning, and while it represents a partial shutdown, it’s still going to be an inconvenience for riders.

It’s going to be a long 15 months for L train riders.

Construction is underway to repair damage to the Canarsie tunnel, in need of long-awaited improvements after the damage caused by Superstorm Sandy.

MTA workers are handing out information to riders on L train platforms and urging them to plan ahead.

There won’t be a full shutdown, as initially planned.

Earlier this year, Gov. Andrew Cuomo did away with that option, opting instead for a partial shutdown that would still allow for modified train service.

For the next 15-18 months, service will be reduced on weeknights and weekends.

Between Manhattan and Brooklyn, trains will run every 20 minutes.

Within Brooklyn, east of the Bedford Avenue stop, trains will run every 10 minutes.

“It’s a relief that it’s not going to be shut down entirely, so it’s the lesser of two evils,” said commuter Brittany Mylov.

“It’s going to be completely congested in the subways, obviously there’s going to be a lot tension, a lot of angry faces coming out the subway,” said commuter Armin Maneshi.

Customers are urged to use alternative options to help ease the expected overcrowding.

“We’re really urging people to use it, really fast bus connections between the L train stops and the J-M-Z stops, use the G train, there’s more service,” said MTA Chief Development Officer Janno Lieber.

Still, it’s going to be an inconvenience – one an MTA conductor fears could easily cause chaos.

“You’re not even going to get down to the platform. You’re going to be stuck in the mezzanine waiting to get down to the platform. That’s a setup a for a riot down here,” said subway train conductor John Ferretti.

The MTA says it is working closely with the NYPD. It is also working with the Transport Workers Union Local 100 to monitor the situation.

There are no plans to alter service during rush hour Monday-Friday.

Still, the best advice is to plan ahead.

Transit Authority chief Andy Byford praised what he called a successful first day during the slowdown.

“I was really pleased with how today went. We maintained regular train service intervals throughout the day, coping well with medium to heavy passenger numbers on both sides of the river. We will continue to refine the plan in coming days, but for now, I am very proud of my team and our NYPD partners for their highly professional job so far and I’m grateful to New Yorkers for their patience and good humor while they got used to the revised service,” Byford said in a statement Saturday night.

For more information on the L train slowdown and MTA routes around Brooklyn and Manhattan, click here.