Based on comments to the excellent report on the Coastal Tramway in Belgium, I think needed is some clarification of what an interurban is. Most new light rail lines provide transportation between suburbs and city centers. Interurbans may or may not do that, but they definitely connect centers, which the Coastal Tramway does, more than two or three along its route.
Pittsburgh had interurban lines south to Charleroi-Rosco and Washington. Cut back to their present length, they are suburb-to-city light-rail lines, not interurbans. St. Louis’s line to Bellville is an interurban because Bellville is an employment and retail center. As are Milwaukee, South Bend, Michigan City, and Elgin. If Baltimore’s light rail system were extended to Annapolis and/or to Silver Springs (connection with Washington, DC’s Metro), then it would be an interurban system, not just light rail. Boston’s system is definitely just light rail, not an interurban system. And a multi-metropolitan streetcar system cannot be an interurban unless substantial trackage is off-street. Two examples in New England were the New York and Stamford (New Rochelle – Stamford) and Boston and Worcester. The Eastern Massachusetts lines north to Revere, Lynn, and Salem were very marginally interurban north of Revere. Los Angeles’s Blue Line to Long Beach is an interurban and is even mostly on the old Pacific Electric RoW with similar street-running in Long Beach.
The Vienna Baden line in Austria is an interesting interurban line. I rode it in 1960, with prewar wood mu cars, a two-car train. (Now getting modern low-floor cars.) Now I believe there is a stretch of trolley-subway running in Vienna, but then it was a
The consensus tends to define an interurban as electrically powered, with direct suspension overhead and trolley pole pickup. They are built to lower engineering standards than steam railroads with tight curves and lighter rail. Equipment is shorter and narrower than steam roads, using radial couplers to handle the curves. Freight service is minimal to non-existent. Service tends to be frequent with one or two car trains between relatively nearby cities.
I’ve usually taken the lazy man’s approach and described interurbans as trolley cars on steroids, that is bigger, heavier, and faster, and instead of traveling between neighborhoods travel between towns or even counties.
Trolley and interurban are terms that have fallen by the wayside. Transportation planners seem to have replaced them with Streetcars for what we used to call trolleys, and Light Rail for everything else short of rapid transit.
All the above is true, but still historically correct terminology can be helpful. Does anyone have the fine Hilton and Drew book and can quote their definition?
Switzerland is building a new interurban line. Basel, the Capitol, and Zurich, the largest city, are connected by a main-line electrified railway with frequent passenger service. But smaller communities beween are currently more conveniently served by a bus route. So an interurban line is being built between the Zurich suburb or Alseiten and the Basel suburb of Kilwangen. At both ends it will connect with the local tram lines and also with the railroad local passenger service. There is also a raiload transfer connection at Dietikon, about midway. Not clear about thorugh running at each end over the local tram lines, but it should be possible. All are meter gauge, except the railroad.
The Northern Electric (which later became the northern half of the Sacramento Norther) was a third rail interurban. The Central California Traction was also third rail, energized at 1200V.
The plot thickens, I think, when you look at the definition a bit more empirically.
Little doubt in my mind that the ‘electrified’ part is largely circumstantial, driven by contemporary trends in technology and economics that were sometimes extremely transient. By the time practical diesel truck motors and associated transmissions (epicyclic, fluid, or even improved friction-clutch) were available, had there been remaining demand for interurbans in general you’d have seen extensive ‘dieselization’ or even conversion of older equipment to motor rather than wire use.
Likewise, a big part of “interurban” service was that it served the region between the urban points. Third rail wasn’t only deprecated because of capital-related reasons and power losses: it was considerably less safe for passengers to board or depart a car at non-platform locations or the usual sort of flag stop.
P&W in Philadelphia is an interesting case: it wasn’t an ‘interurban’ at all, but a steam railroad converted to run interurban-type cars, with some interurban-type amenities appended to it – a case could be made for similarity with the New York Dyre Avenue #5 line (or the prospective run-through of cars on the NYW&B as originally mentioned) where the operation on the dedicated part of the ROW was anything but ‘interurban’ style.
Meanwhile, we have the push in the '20s toward increased speed, which is fundamentally difficult to reconcile with a number of ‘interurban’ service features even given the overload capacity of electric MU traction for rapid acceleration (and true regenerative dynamic braking that ‘might’ be practically used for power cost saving as well as brakeshoe conservation). As noted, if you can preserve the useful part of serving demand that does not easily parcel into stations, providing high speed on other parts of the route adds to perceived value and ‘take rate’ for
Actually, the overload of traction motors was solved for mu cars at the same time it was solved for diesel locomotives, by the AC hysterises-non-sychronous brush-free computerr-controlled motor, which is now in use in nearly all diesel-electric and electric locomotives, streetcars, light-rail cars, trolley and battery buses, and sububan mu cars. As an economical-with-regard-to-land-use solution to highway congestion, light rail is making a comeback, and in certain cases its characteristics put it sqarely under the definition of an interurban line. St. Louis - Bellville, Los Angeles - Long Beach are probably the purest examples.
Regarding SEPTA’s 100. It is a suburban light rapid transit line. In some respects it is an interurban line, but it is completely grade-separated, which certainly means rapid-transit, not interurban. Up to sometime in 1949, it did regularly host genuine interurban cars of the genuine interurban Lehigh Valley Transit’s Liberty Bell route.
Even though it is not electrified, I would label the Camden - Trenton NJT River Line a “Diesel Interurban,” because in all other respects it operates like a typical interurban, including street-running in both Camden and Trenton.
Don’t forget Iowa’s CRANDIC. It traveled between Iowa City and Cedar Rapids and wasbetter known as the “Vomit Comet” during WWII when Navy trainees rode up to CR for fun & games**. I rode it to go home at Thanksgiving and Christmas, connecting with C&NW to Carroll IA.**
Regarding Iowa, should we consider the Mason City to Clear Lake line of Iowa Traction to be a still electrically operating interurban, although now for freight only?
Probably not. It certainly is an ex-interurban, and now can be called a freight-only interurban or an electric freigiht switching railroad like Niagra Junction was.
I have heard the Mount Mansfield Electric RR, that ran about a dozen miles from Stowe, VT to the CV connection at Waterbury, referred to as a rural trolley. The line folded in the depression shortly before the CCC cut ski trails on Mt Mansfield. If it had only held on a little longer.