Next Stop: Secaucus

Before long, the Manhattan terminus of the No. 7 train will move west, from Times Square to the Hudson Yards on the far West Side. That’s good, but renewed talk of extending the subway line under the Hudson River to Secaucus in New Jersey is even better.

The extension came up for discussion again last week when a preliminary study of the plan showed that costs would be significantly lower than the $9 billion it would have cost to build a commuter rail tunnel under the Hudson for New Jersey Transit riders. New Jersey Governor Chris Christie killed that tunnel project, dubbed Access to the Region’s Core (ARC), earlier this year, arguing that the true cost of the ARC project might reach $15 billion, a figure he described as too expensive.

Mayor Bloomberg reiterated his support for the No. 7 extension last week after a preliminary report noted that the subway line would not require the capital costs associated with the ARC tunnel project. Mr. Christie also supports the plan as an alternative to ARC.

So it’s full steam ahead, right? Well, no. The Metropolitan Transportation Authority, which is trying to plug a $10 billion hole in its capital budget, is not particularly enthusiastic about taking on another capital project. (The M.T.A. operates the city’s subway system.) Extending the No. 7 train to the Hudson Yards will cost about $2 billion, and the M.T.A. argues that its energy and resources are dedicated to completing that project and several others as well.

The agency may be right to be wary of spending more money on politically popular projects. Nevertheless, the No. 7 extension deserves serious consideration. Access to Manhattan remains critical to the region’s prosperity. The No. 7 project would make access to Manhattan and even the far reaches of Queens easier for New Jersey residents and commuters. That would be a plus for the entire region.

Next Stop: Secaucus