Alon‘s had a long-running series on the comparative construction costs of transit modes in different countries. It’s good reading.
At the same time, I’ve always been a fan of the “Interurban Option” – running commuter-rail levels of service to low-density areas using rolling stock that is compatible with inner-city LRT systems. I’ve previously suggested that North Carolina’s research triangle would make an ideal location for such. But in order for lower-ridership/lower-frequency LRT to work, you need lower-cost LRT.
The other night I was reading up on the history of the Chicago’s Skokie Swift (“yellow line” in the blandified, post-World-Cup naming scheme). Chicago has a long history of interurbans operating over the “L” network. The North Shore came in on the Howard line, while the Roarin’ Elgin got on the Congress “L” at Forest Park. These trains operated all the way to the center of the loop, as contrasted with other cities where interurbans ended at suburban terminals (e.g. Philly-69th) or duplicated the streetcar system (e.g. Pacific Electric). This kinda thing should work.
But back to Skokie. Construction was ridiculously cheap. Catenary had been pulled down when the North Shore Line folded, but a few miles of third rail remained extant. Rather than rebuild catenary over the entire route, wire was hung only over the unelectrified portion. To switch, trains built up speed, coasted past the end of the third rail, and raised a special bespoke pantograph designed by the PM, to switch to wire. This continued until 2004.
This sort of inexpensive construction wasn’t unheard of in the 60′s and 70′s. The San Diego Trolley originally used street-level boarding (this was pre-ADA). Calgary’s C-trains didn’t have air conditioning until quite recently (and some still don’t). Portions of Portland’s MAX and Bmore’s LRT were single-tracked, though the latter proved short-sighted.
Similar cost-containment would be needed to make Interurbans a success. For instance, the Skokie Swift carries 7,000 riders daily. At current prevailing costs, a double-track LRT line of the Skokie Swift’s length with an ultimate ridership of 7k would have to be considered a failure, not worth the effort, fodder for a Randal O’Toole piece on the superiorities of bus rapid transit. But 7,000 riders would be quite respectable for a single commuter rail line. Many of the legacy Philly lines operate in this region, while New Mexico’s Rail Runner (my personal favorite FRA-compliant New Starts project) carries only 4500.
So let’s talk about what it would take to make Interurban – LRT vehicles at commuter rail frequencies – work.
USE WOODEN TIES
This one’s pretty simple. Wooden ties don’t last as long as concrete, and the heavy federal match on most rail projects biases everything in favor of high capital cost/low operating cost. But wooden ties are *cheap*. This is the reason historically pretty much every railroad everywhere has used them. Moreover a rail tie which sees 20-minute peak headways and 60-to-90-minute headways elsewhere is going to be subjected to a lot less stress than a core LRT trunk running every 7 minutes. And while the “best practices” recommendation in your project plan (and your cost benefit) is going to recommend replacement on 20-year intervals, deferred maintenance as practiced by all legacy US operators will see lightly used wooden ties pushed out to a 40 or 50 year lifespan.
USE TROLLEY WIRE
Most US LRT goes in with catenary befitting a German mainline railway. This is, again, an outgrowth of the US transportation culture’s bias towards front-loading capital costs. Trolley wire is cheaper, but wire is more difficult to keep properly tensioned. The upshot is that on a low-traffic railway, you can have slack wire and it’s still all good. Sure, the increased friction from slightly slack wire increases wear on both wire and pantograph. But when you’re talking about a system that runs 90-minute off-peak headways, this is trivial compared to the cost of the primo stuff. Along with trolley wire, you should also
USE WOODEN POLES
You can start to see the common dynamic here. Wood is cheaper than steel, but doesn’t last as long. What’s better? Electric utilities public and private invariably choose wooden poles. Only with trains do we start with stainless.
USE SMART SINGLETRACK
This is where the commonality ends. Single-track operation needs to recognize two facts. First, if the line gets busy enough, double-tracking will be required. Secondly, trains sometimes run late. Therefore, single track operation needs two components to be effective.
BUILD PASSING SIDINGS AT EVERY STATION
Trains are enclosed spaces. LRVs are more enclosed than commuter trains or Amtrak, since they’re not vestibuled. For this reason being on a train that’s stopped in the middle of nowhere can be sort of disconcerting. Moving all meets to stations means the train chills for a couple minutes with the doors open (or if it’s hot outside, with the doors openable by pushing a button). This is much more pleasant for the passenger.
Moreover, delays can and do happen. Attempting to VE out passing tracks based on a sound operating plan will only lead the system to be obsolesced sooner. A stop every couple miles with a passing track is good for 10-minute headways. A stop every mile with one is good for a bit over 5. This sounds like overkill until the 5:53 gets delayed by a fair trade protest until the 6:07 and the 6:32 are right behind it.
USE ISLAND PLATFORMS AND AVOID OVER/UNDERCROSSINGS
Pedestrian overpasses on low-frequency rail lines can be justified where there are multiple tracks, which are also used by 79mph freight trains of death that take eight miles to stop. However, most every LRT out there is capable of a 3.0mphps deceleration rate or better, which lessens the need for ped grade separation.
With at-grade ped crossings, island platforms are much safer because there is no “multiple threat” issue. The platform itself serves as a pedestrian refuge, and if there is access from both sides a “zig zag” sidewalk can be used so that all peds cross in front of or behind the train. Different agencies appear to have different preferences in this regard. Island platforms are also optimal from an operations perspective, since you can “wrong rail” trains without any inconvenience to passengers. Among other things, this allows express trains to pass locals.
LEAVE ROOM FOR EXPANSION
In practical terms, this means that a single track should be built off-center, so that it becomes part of a later double track. At a minimum the distance off the ROW centerline should be half the minimum track spacing (e.g. 6 to 7 feet), but ideally there’d be enough room for a second track under construction as well as a row of construction vehicles. This probably means grabbing a 10′ easement along the property adjacent to the future second track. In most suburban contexts, the cost of this easement will typically be a fraction of a second track, even if you factor in the the discounted cost of a second track 20-30 years in the future.
AVOID INDUSTRIAL RAIL CORRIDORS
In theory, running next to rail corridors is a great idea. In practice, this only works if the adjacent land uses don’t have rail service. Otherwise you end up like Dallas or San Jose, building gigantic multi-mile concrete bathtubs to take LRVs over industrial leads that see one train every three weeks.
LOOK FOR “SNEAKER” ROUTES
A lot of suburban commercial strips have relatively continuous boundaries where the backs of the stripmalls and big boxes end and single-family homes behind. Teasing a rail line through this boundary region requires a ton of strip takes and probably some people’s backyards, but once this is done you’ve basically got grade crossings every 1/4 to 1/2 mile and there’s enough queue storage space between the gates and adjacent traffic signals that you don’t need to spring for a fiber interconnect. Basically the rest of your design takes care of itself.
Similar routes exist along old land survey lines. Master-planned communities of the Woodlands/Highlands Ranch/Summerlin variety tend to make up only a fraction of the urban form. The rest of it is built out piecemeal, so that the original outlines of 50-100 acre plots can be seen from the air. In the Mountain West and the Plains these are often half- and quarter-sections; in Texas and the East they’re a little more esoteric. Following these lines you can grab parking lots, yards, etc. Garden complexes are particularly easy to work with since you can take out the strip of parking along the fence, raze a building, then reconstruct the parking in its place.
All of this drives up right-of-way costs, but you also get to minimize capital and O&M outlays. And the cash saved by using a “free” roadway or highway ROW is easily wiped out by median paving or overpasses at interchanges. Basically you want to find an alignment that lets you use cheap construction, instead of trying to find a cheap alignment and then letting the construction cost chips fall where they may.