Since World War II, as rail lines — passenger and freight — were abandoned, some of the rights-of-way were converted into bike paths, most famously around here the East Bay Bike Path. Bike paths are nice, but commuter-rail lines on these old rights of way would do far more local environmental, social and economic good — year-round.

The East Bay is particularly adaptable for commuter rail: a densely populated and narrow strip with many people who must travel in and out of Providence every day. Commuter service between Providence and Bristol (and ultimately Newport) would take a lot of traffic off Route 195. It would be well worth doing even it meant moving or otherwise disrupting the bike path in some places.

In the West Bay area, of course, the Amtrak right of way provides possibilities for regular commuter service between Providence and, say, North Kingstown — a commuting corridor since before the turn of the 20th Century. Also, a new line could be laid along parts of Route 95 itself, as is some of the MBTA commuter line along the much hated Southeast Expressway (or Distressway as it’s often called) serving the southeast suburbs of Boston. (That would also be a good way to encourage people to take the train: Automobile commuters stuck in traffic jams would see the trains whizzing on by . . .)

Amtrak and commuter-rail systems don’t have enough track. In American metro areas, we need to start thinking about laying more track — which may mean actually taking over roads for that purpose, in an amusing public-works reversal. Not all places have the population density and other attributes that justify laying new track, of course, but Greater Providence does, with a vengeance. And a reminder: The Providence suburbs referred to above used to have commuter rail!

Cheap gasoline, the lure of a suburban acre, creative home-mortgage financing and heavy lobbying by politically connected road contractors doomed many such commuter lines in old American cities.

The world, however, has vastly changed, as those who have filled up their gas tanks lately may have noticed. The age of relentless new-road building is over, thank God. The imperative is for track laying.