Costing the City Branch Line

Long ago, I suggested the possibility of a long-term subway line running from 8th/Oregon (Pennsport) to Ridge/Henry (Andorra), the first phase of which would run between 8th/Market and Girard via the City Branch cut and part of the Ridge Avenue Spur. It looks like this.

A very old map. For one thing, my station naming principles have changed since.

The next obvious question is, how much does it cost? Actually, answering this question is substantially more advantageous than other potential heavy rail lines (or even Phase Is of lines), as the routing proposed runs along a former (abandoned?) freight right-of-way in heavily redeveloped (or redeveloping) areas where industrial uses are obsolescent: Franklin Town* and Callowhill. People live--not work--in these areas today.

This routing has four key components:
-The Philadelphia Branch from Girard to Noble. This follows the last mile or so of what was once the B&O's Philadelphia mainline, and is parallel to the single-track CSX main on what is at least a four-track (possibly six-track) right-of-way. It also includes a 1/3-mile section in the Fairmount tunnel, between Noble and Park portals.
-The City Branch, along the former course of Noble St. between Broad and the Noble portal, just west of 22nd. Like the ex-B&O ROW, this is a very wide route that is in disuse due to the postindustrial evaporation of its customer base. East of Broad, the City Branch continues on an elevated structure to connect into the 9th St. Branch and the approach to the former Reading Terminal. This elevated structure network (extant from Vine to Fairmount, and from 9th to 13th) is now known as the Reading Viaduct.
-A new tunnel from Broad, along Noble, to an at-grade (no flyunder) junction with the Ridge Avenue spur between 10th and 11th Sts. This tunnel would include a new Callowhill station between 11th and 12th Sts. and a short stretch of 4% grade in order to clear under 13th and between Broad and the existing subway tunnel and portal onto the City Branch's former elevation.
-The Ridge Spur from Noble south to 8th and Market.

Acquisition of the existing parts of this right-of-way is the initial hurdle: CSX is infamously recalcitrant when it comes to giving away parts of its right-of-way. However, there is little economic justification for holding onto this stretch, as the Fairmount Tunnel has been single-tracked to maximize clearance**, particularly due to the ancient (and constraining) south portal, just under the proposed Paine Park site, the duplication with the double-stack clearing ex-PRR High Line trestle across the river, and the single-track bottleneck of a concrete-lined cut by Wayne Jct.; the lack of any active customer in the immediate area; and finally the slow speed limit of this stretch caused not by engineering so much as the sheer congestion encountered in an urban area--particularly the approaches to the Schuylkill Banks. However, as the Banks themselves have proven, CSX is willing to let go of obsolescent stretches of its right-of-way***, and a good deal of the right-of-way width between Fairmount Tunnel and Fairmount Jct. is nothing if not obsolescent.

Procurement of (portions of) the existing railroad easement, wherever not already in the public realm, is thus the first major expense this project encounters. Mercifully, however, it is short: one mile along an obsolescent section of an active right-of-way, and two-thirds of one along an inactive one. $30 million for acquisition costs seems like a reasonable estimate.

Since the meat of the project is basically the linking two separate railroad rights-of-way together, the greatest cost would be expected to be in the actual interlinking itself, especially one that (a) is underground and (b) requires engineering with finesse. While tunnel construction should be (for the most part) cheaply done via cut-and-cover, due in part to the lack of major commercial or residential uses along the vast majority of the 3.5-block-long section, it would also have to be built under 13th, into the Branch between Broad's street grade and its subway grade, and with a gallery area for the Callowhill subway stop between 11th and 12th^, would be done for close to the minimum possible cost of a true subway under U.S. labor conditions--but it is still a subway, and may well breach the water table when it passes under 13th, and thus will be expensive. $50 million sounds like a reasonable cost estimate^^.

The final major expense is what could be best called "installation of railroad technology", namely, the rails and ties, equipment, third rail, platforms, platform access, and turnstiles. Since I'm attempting to utilize the most cost-effective possible alignment, most further savings (howsoever incremental on an individual basis) can be made in this arena. For instance, the cars currently in use on the Broad-Ridge Spur would be re-assigned for this line. No new equipment = $40 million cost savings. Platforms would be 100 feet long, or just about the length of two BSL subway cars (why would they need to be longer?) and built out of wood, wherever feasible (Broad, Franklin Town Park, Rodin Museum, Lemon Hill, Girard), offering a cost savings of a few million. Instead of needing to install an expensive new ventilation system in the Fairmount tunnel in order to deal with the diesel fumes, the CSX section would be simply walled off from the rapid transit section, and the two tunnel sections would alternate between the existing ventilation shafts (which were originally engineered for the significantly greater emissions of steam traction). Few barriers are as effective as physical barriers, anyway. Cost savings: Quite a lot.

While an elevator (or two) would have to be installed at Callowhill, Fairmount, and Art Museum each--due to these stations' being underground--at all of the other stations, a pedestrian ramp (also made of wood) would be able to satisfy ADA requirements.

So there are essentially three elements that spending actually has to be done on to finish this project: (1) extending the track down our fresh new ROW, along with the third rail needed to power our equipment, (2) building a cinder block wall down the middle of Fairmount Tunnel to divide diesel and metro ventilation districts (and the masons would be used to build the Fairmount and Art Museum station platforms too)--the tunnel being shallow enough that approximately 1/2 of the current ventilation shafts should allow acceptable air exchange--and (3) installing wood platforms at all of the other stations. Where the ROW parallels the CSX line, a chain-link fence is also a must-install, but that should frankly be about the same as what an exurban homeowner would expect to spend at the Home Depot to completely fence a two-acre lot in. Perimeters rake up mileage real quick. I recall that laying track costs about a million per mile, so we'll cost this at about $10 million and give the masons and carpenters $4.5 million each to play with.

The final cost is a contingency fund, a hedge or allotment set aside to deal with unexpected expenses. This is usually about 10% of the project's total projected cost, which at this point would be $9 million ((50+30+10)/10); since we are already costing out with a tight cost ceiling, we'll give this contingency fund an extra mil, and make the total cost projection $100 million even.

$100 million is borderline for Small Starts (unusual for heavy rail projects; Small Starts as a grant mechanism favors light rail and commuter rail), and since we're aiming for about 10,000 daily riders (~1,111 riders/station)--not too bad considering that the combined population of the Census tracts immediately abutting this proposed line is 27,344, and thus fully in line with relative ridership on heavy rail lines in similarly dense areas in New York, Boston, Chicago, and Washington, D.C. At these (optimistic) projections, the cost per mile is $33 million, and per passenger, $10,000. Even if half the proposed ridership is actually attained, the cost per rider would be $20,000, still extremely low by heavy rail standards and well in line with light rail standards.

Sometime in the near future I hope to dwell on non-financial justifications for this line's existence and programs that SEPTA can run in concert with lineside destinations to increase usage.
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* Fun fact: The Baldwin Locomotive Works, the biggest American steam locomotive builder, was once located in Franklin Town, running between Callowhill and Spring Garden and Broad and ca. 20th. This helps explain the paucity of historical rowhomes in the area.
** Like the Howard Street Tunnel in Baltimore.
*** To my knowledge, the B&O easement originally extended to the river. Part of the Banks is, for example, built over 24th St. Sta.'s coach yard.
^ With the expectation of, if not a wholesale plan for, redevelopment of what is currently a transformer array in the station's immediate area--an array that is supposedly being replaced by a new one along the former Viaduct; such station-side development tends to greatly improve ridership.
^^ Based on the assumption that a mile of subway costs $100 million (a number I've heard thrown around for the Navy Yard extension) and considering that the actual tunnel length will be just shy of half a mile, with a bit extra thrown in for a cost cushion; an electrical substation, for example, may need to be built out by Girard somewhere.