Riders and officials celebrating the completion of a 116-year-old tube.

It’s one of four that make up the East River Tunnel. But there’s a whole other tube that needs to undergo the same rehab, and that has the MTA concerned.

NY1 got to take a train ride in both tubes, and riders can see a difference.

The two tubes were heavily damaged by Hurricane Sandy because silt clogged the drains and flooded the tunnel.

It took 13 months to demolish 24,000 feet of bench wall, all the concrete in the nearly 3-mile tunnel down to the liner and rebuild it to modern safety codes with new tracks, drainage, power and communication systems.

According to officials, the tube can now quickly recover if there is another Hurricane Sandy. But MTA officials had concerns with one of four tubes out that issues would arise and impact service.

The MTA said it demanded crews be on standby to address them, among other measures. According to the agency, without those demands, things could have been worse.

“Amtrak achieved a milestone. So we’re going to keep being a millstone around their necks to make sure that Long Island Railroad customers don’t get not, you know, don’t get canceled trains and shut down service like they did on four or five occasions during this project,” MTA Chair and CEO Janno Lieber said.

“We have plenty of work ahead to rehabilitate the second tunnel, too. And we’ve learned many lessons that we are ready to implement as we undertake that work over the next three months,” William “Byl” Herrmann, the interim president of Amtrack, said.

There were several track issues. Fires and debris on the track which affected service, not only for Amtrak but also the LIRR and NJ Transit.

Riders were happy to hear the four tubes are all now working — even if one of them is going to be shut down for work soon.

Amtrak said it has encountered what they called tunnel gremlins along the way and discovered it needed different equipment, concrete pumping systems among other things that it believes should make the second tunnel’s work go more quickly.

Amtrak is doing an independent review to identify ways to help in that effort before work starts on the other tube this fall.