With ceremonial shovels at the ready, officials gathered early this week to herald the start of work on a three-block-long, hurricane-proof, $185-million passenger-rail easement to nowhere.

Perhaps that's a bit harsh.

The hope is that this concrete box west of Penn Station in the Hudson rail yards will someday be a pathway for the Amtrak and New Jersey Transit trains that serve Penn Station -- allowing them to roll easily into and out of the terminal by way of a new trans-Hudson crossing.

Unfortunately this tunnel doesn't exist.

It's been planned, debated, funded and defunded -- the last time in 2010 by New Jersey Gov. Chris Christie, who said the state lacked the cash.

So for the indefinite future, Amtrak and New Jersey Transit will continue to run 1,300 passenger trains a day through two thoroughly inadequate 103-year-old tubes into America's busiest train station.

But why build an expensive rail easement -- now -- through the Hudson Yards? Can't it wait until we have a new tunnel?

No. The MTA leased air rights over the Hudson yards in 2010 to private developers who plan to build a platform over the site for a massive commercial and residential complex. That's great news for the MTA and proponents of the development of Manhattan's Far West Side.

But it forces the hand of politicians who must figure out how to fund the region's transportation infrastructure.

Amtrak must put a new easement into place now for a future tunnel -- even if no current plans exist. The cost of building an easement after the rail yards are enclosed would be insanely expensive.

The box to nowhere says it's time for transit funders -- in Trenton and in Washington -- to get off the dime and build the tunnel our region has needed for years.

We're looking at you, Chris Christie.

The city is moving in a fast-forward mode. That's a plus for New Jersey residents as well as New Yorkers.

Our rail system needs to keep up.