In the classic 1981 film “Escape From New York,” Manhattan circa 1997 has been turned into a giant federal prison with all exit routes blocked. Anyone relying on Penn Station these days will find it familiar.

In “Escape,” Snake Plissken (Kurt Russell) must rescue the president from hostage-takers and escape within 22 hours because he’s been wired with explosives, which will detonate at 22:01.

Snake had it easy.

Perhaps in Robert Rodriguez’s coming remake, Plissken will have to do something far more arduous: escape New York City by buying a one-way NJ Transit ticket and taking the train out of Penn Station to freedom.

It’s harder than it looks.

Tuesday night’s commute was snarled again by electrical problems and delays to the point where, The Post reports, “police officers were spotted turning people away around 5:30 p.m. near 34th Street and 7th Avenue due to overcrowding issues.” That’s right: Penn Station couldn’t hold any more people.

Monday’s commute wasn’t much better. In fact, since the station saw two train derailments in 10 days — an Amtrak train on March 24, then an NJ Transit one on April 3 — service has been atrocious. Long Island Rail Road, meanwhile, has seen three major service disruptions this month at Penn.

“Atrocious,” however, is only slightly worse than the normal state of affairs: terrible.

And it’s about to get worse: Amtrak (which owns the tracks) is prepping repair work that will put one track at a time out of commission for extended periods during the week. The delays, NJ Transit warns, will be “effective immediately and continuing until further notice.”

No real details are available yet, which gets to the heart of the problem here: Commuters can handle delays if they’re able to prepare. But Amtrak, NJ Transit and the LIRR usually keep travelers in the dark. (It’s the one thing they can agree on.)

That’s always obnoxious, but this time it’s utterly unacceptable. Commuters have to plan. They must decide whether to buy daily, weekly or monthly passes; if they’re going to be forced off NJ Transit halfway to work, they need to know what bus or PATH tickets to buy.

The many commuters who pay for parking passes at their local stops may want to skip it this month, if the train’s no longer their best hope of making it to the city.

Also: Do you need to leave at 6 a.m. to be to work by 9, or at 5?

What commuters need: a full plan of action explaining not only the new train schedule (one the railroads can actually manage to stick to) but also the alternatives being made available, as well as at least best guesses on the duration of the disruption and the cost.

This goes to a larger problem with Penn Station: Officials never prepare until it’s too late. The station is poorly designed to handle passenger traffic, but perfectly designed if the intent was to create a hellish deathtrap.

Example: On April 14, as commuters and tourists packed the station amid delays, a police officer fired a stun gun at someone causing a disturbance; the crowd thought it was gunshots and stampeded, injuring 16.

Gov. Andrew Cuomo’s response: “The first responders have to be trained not to panic and they have to be trained how to now handle a public that is very antsy.” Oh, is that it? “It’s a totally new world we’re living in,” he added, raising the specter of terrorism.

Except it isn’t a new world, and you can’t drill commuters for an orderly exit from the sardine can.

Here are a few facts for Cuomo and any other officials who still don’t get it:

Though it was built to handle about 200,000, Penn Station today sees 650,000 pass through its urine-stained entrances — more than New York’s airports. By 2040, that number is expected to swell by another 200,000 riders, nearly half of whom will come from New Jersey.

North America’s busiest station also handles 1,300 trains daily.

North America’s busiest station also handles 1,300 trains daily. Last year, NJ Transit had more trains break down than any other commuter line in the country, reports the Federal Transit Administration.

While its service might be arguably the worst in the nation, NJ Transit train commuters “pay the highest fares of the nation’s 10 biggest commuter railroads, including those run by New York’s MTA,” according to a study reported by NJ.com in 2015.

The worst service at the highest price. And the result is the country’s busiest station in the heart of New York City — with Madison Square Garden directly above it — becoming uninhabitable except for the vagrants who have turned the building into a dormitory.

Of course, finding alternative routes isn’t so simple. The train trouble has been forcing the diversion of some trains to Hoboken Terminal, which still has several tracks closed thanks to a derailment in March.

Snake Plissken would have his work cut out for him.