What if we could get out of our cars? What would Long Island be like with better public transportation, with a thriving Long Island Rail Road at its center?

Can Long Island become a suburb that keeps and welcomes younger residents and workers who don’t want to use their cars, where transit-oriented developments, with apartments, offices and retail, are built across the region?

The Island’s growth always has been tied to its rails, and the network is still critical. At more than 180 years old, the LIRR is the nation’s busiest commuter rail system, with an annual ridership that soared past the 89 million mark last year. An LIRR makeover would take that higher and ripple through the economy, increasing home values, expanding employment and changing the region for the better.

The makeover’s elements would include more frequent railroad service and increased capacity, more train storage and a local command center, and removal of the busiest and most dangerous grade crossings. Long Islanders also need more accessibility, parking and pedestrian connections, and improved stations, platforms, tracks and signals. Together, this would require a stunning $5.6 billion investment in Long Island.

Amazingly, it’s happening now.

In a speech last week in Woodbury, Gov. Andrew M. Cuomo took the region’s business and political leaders for a trip down the tracks to illustrate how the newly approved MTA capital spending plan and improvements already underway will work.

There are 100 individual projects that should transform the LIRR into a safer, more reliable system that would relieve congestion, unblock bottlenecks, and make taking the train a superior commuting alternative.

Capacity, Cuomo said, could increase by up to 81 percent in the evening rush hour. That might be a stretch, but “build it and they will come” has worked before.

In his speech, Cuomo’s tour started at the western end, improving the terminals by remaking the old Farley Post Office in Manhattan into Moynihan Station and upgrading Jamaica with new tracks, switches, and signals, and extended platforms for longer trains. Together, that’s nearly $2 billion worth of work.

Then there’s the long-delayed but oh-so-critical East Side Access effort to connect the LIRR to Grand Central Terminal. Cuomo touched on it briefly, but he should speed up its opening, too.

As for everyday needs in Nassau and Suffolk counties, the conversation is all about capacity and frequency. The newly approved third track on the Main Line will create a way to bypass train breakdowns and other problems while providing more train travel in the opposite direction during rush hours. Construction will start next year.

For those who point out the third track is only 9.8 miles from Floral Park to Hicksville, the double track from Farmingdale to Ronkonkoma will be done next summer, 16 months ahead of schedule. It will open one of the Island’s worst bottlenecks. With a single track, delays occur anytime a train is disabled on the Ronkonkoma branch, or one train has to wait for another going the other way. A double track will help.

With so much talk of power and signal problems, upgrades there will make a real difference. The MTA plans to replace power throughout the system with 20 power substations added or rebuilt. Signals will be upgraded, and technology called positive train control will make the LIRR safer. There are plans to build a new 13-acre train yard in Ronkonkoma, which will store extra trains so they’re ready for the morning rush, and a command center to bring those making decisions closer to home.

Some improvements are more visible: the elimination of seven grade crossings, the lifting of several bridges to avoid truck collisions, parking for 3,500 more cars, and a host of sound walls. Also coming: upgrades and renovations to 39 stations, from East Hampton to Hicksville to New Hyde Park.

Some of the money, such as $1.95 billion for the third track, is allocated in the current MTA capital plan. Some, including funds for Moynihan, will come partly from the private sector.

These plans don’t solve all of the LIRR’s deficiencies. They can’t fully address, for instance, the East River tunnels. Upgrades are necessary. But Amtrak owns and controls the tunnels, and has to find the money and get the work done, or turn over ownership and control. And unmentioned by Cuomo were the LIRR’s other needs. One example: The Port Jefferson and Babylon lines should be electrified in the east.

These transit improvements should spark ever wider transformations in nearby communites, making them destinations. This will help the Island entice young workers to stay here and commute here, which in turn will provide the talented workforce businesses will need to thrive. Such transformations are already underway in Farmingdale, Ronkonkoma, Patchogue and elsewhere. Hicksville and Hempstead are among other spots ripe for similar change. In the right places, private developers could be partners in public improvements, too.

Now more than ever, there are open tracks and green lights ahead.