“Subway” Cars Could Share the Interborough Express Line with Freight Trains
The tunnel at Metropolitan Avenue in Middle Village on the proposed Interborough Express (IBX) transit line, under part of All Faiths Cemetery, is a subject of controversy. It is wide enough for only two tracks. The MTA says it cannot be enlarged to accommodate two tracks each for freight and transit, because of the cemetery above.
The MTA offers only two alternatives to permit both freight trains and transit to travel through the area: a new, longer and deeper tunnel costing about of 2.9 billion dollars or use of Light Rail Vehicles (LRVs) for the entire IBX line. They would bypass the Metropolitan Avenue tunnel by running through the streets of Middle Village. (See “Street-Running LRVs on the Interborough Express Line is a Bad Idea” at https://bqrail.substack.com/p/street-running-lrvs-on-the-interborough)
There is another alternative, successfully used on other systems, which is time-sharing of tracks in the existing tunnel by freight and transit. That would permit use of existing subway-type railcars, such as those used on the PATH system or on the NYC transit’s A Division (numbered lines, which I refer to as “IRT-type” cars.) The MTA, however, has categorically rejected that alternative, writing to me, “In light of current and future of freight mobility needs in New York City and the region, operationally sharing CSX’s trackage with through [sic.] the Metropolitan Avenue tunnel in Queens is not an option for the MTA.”
This paper addresses those “current and future freight mobility needs,” showing that—in fact—they can be met by time-sharing in the Metropolitan Avenue tunnel.
What Is “Time-Sharing” of Railroad Tracks?
Time-sharing is used when passenger trains that do not comply with Federal Railroad Administration (FRA) rules share tracks with FRA-compliant freight trains. There are three types of time-sharing of tracks by transit and freight trains, all of which are used on the NJ Transit River line between Trenton and Camden, as discussed below:
The simplest and most common is when FRA-compliant and non-compliant trains are kept absolutely separate by assignment of specific blocks of time to each mode, typically one block of time for each mode in a 24-hour cycle.
At one location on the River Line, even during the hours of normally exclusive passenger operation, the use of vital signal design known as Short Interval Temporal Separation (SITS) allows freight trains to cross over passenger tracks. SITS permits short interval shifts between modes while maintaining absolute mode separation in a single zone. (A SITS arrangement probably will be needed on the IBX line, so that freight trains can reach customers on either side of the line.)
An FRA waiver permits Extended Temporal Separation (ETS) on two miles of the River Line, enabling passenger and freight trains to share track, by using signal logic.
According to a 2011 Federal Transit Administration (FTA) report, describing use of SITS and ETS on the River Line, “The template employs advanced but nevertheless ‘conventional off-the-shelf’ engineering technology, the primary element of which is ‘vital’ signal design practice and equipment.”
My Proposal: Extended Temporal Separation for the Metropolitan Avenue Tunnel
I propose that freight and transit cars could share the Metropolitan Avenue Tunnel by use of Extended Temporal Separation. Specifically, I propose that one track be retained for transit at all times, except emergencies, and that the other track be shared by use of ETS. Either existing, FRA compliant PATH railcars or non-compliant IRT-type subway cars could be used.
The tunnel is approximately 500 feet long. In addition, 250 feet on either side would be used for switches connecting the two tunnel tracks to two dedicated tracks each for freight and transit on either side of the tunnel. Therefore, the shared track zone would be 1,000 feet long. The Metropolitan Avenue transit station would be located south of the switches, so that freight trains would not run adjacent to the transit platform.
It would be preferable, and probably necessary, to schedule most or all freight traffic through the Metropolitan Avenue tunnel between approximately 11 pm and 5 am for two principal reasons: (1) that is the period of lowest transit usage, permitting less frequent transit trains, and (2) that is the period of least passenger trains on the connecting Long Island Railroad (LIRR), Amtrak and Metro-North lines, where the freight trains must compete for track time with passenger trains. As shown by the Figure below, in 2012 the LIRR, Amtrak and Metro North tracks on either side of the Fremont Secondary were rated as Level of Service grade F, which is defined as “Above Capacity; unstable flows; service breakdown conditions.” At least in the case of the LIRR, the availability of those tracks for use by freight trains has been significantly reduced since 2012. For example, the LIRR has increased its number of passenger trains by 41% in early 2023.
Transit Timing on a Two-Way Track
The time necessary for a 10-car, IRT-type transit train running at 30 mph to travel 1,000 feet, though the shared track zone, plus the time needed accelerate or decelerate at a station stop just south of the tunnel, is under one minute.
The MTA has proposed that trains on the IBX line run at 5-minute headways (12 trains/hour in each direction), at least during peak hours. Based on train frequencies on the nearby L line subway, and the desire for reasonably frequent IBX trains during the night, I have used a 10-minute headway for the low-usage hours. That leads to the following calculations concerning shared use of a single track for transit trains in both directions:
10% chance of up to a one-minute delay with a ten-minute headway, and
20% chance of up to a one-minute delay in peak times, when there is a five-minute headway.
As shown in the next section, transit trains would only have to use a single track for a total of 60 minutes per night under current freight operating conditions. Therefore, the estimated likelihood of transit delays in off-peak hours due to freight operations in the tunnel is a 10% chance of up to a one-minute delay for 12 trains, or under 2 minutes per night.
Current Freight Train Timing on a Single Two-Way Track
The New York & Atlantic Railroad’s most recent reports claim handling 32,000 revenue carloads annually. The latest reports of annual revenue carloads on the NYNJ Railroad carfloat at Bay Ridge is a bit over 4,000, with some cars going to nearby locations directly served by NYNJ. Therefore, I assume approximately 28,000 revenue carloads travel on the Fremont Secondary. That line is served 365 days a year by a CSX train (occasionally two trains per day) and three days a week, seasonally by the Providence and Worcester Railroad. Based on this information, personal observations, and photographs and videos of operations on the Fremont Secondary, it appears that the average freight train there has approximately 60 cars and is approximately 4,200 feet long. Traveling at 10 mph, a train of that length would take 6 minutes to pass through the 1,000 foot shared track zone at the Metropolitan Avenue tunnel. To allow for variations in speed and train length, I have used 10 minutes for the following estimates of the time freight trains would use the shared track zone under current conditions:
Based on this data, there is no reason why transit and freight cannot share the Metropolitan Avenue tunnel under current conditions.
Possible Increased Freight Train Use of the Fremont Secondary
The only possible, significant increase in freight traffic at the Metropolitan Avenue tunnel would be the result of construction of a Cross Harbor rail freight tunnel, from New Jersey to Bay Ridge, with some through trains continuing onto the Fremont Secondary and north over the Hell Gate Bridge. Most commentators believe the likelihood of the Cross Harbor tunnel being built is very low. A Cross Harbor rail tunnel has been proposed by politicians and planners for over 100 years, but has never been shown to be cost-effective. Also, as indicated in the discussion above, rail freight on the Fremont Secondary is limited by congestion to the North and East. Nevertheless, the Cross Harbor rail tunnel is again under consideration and, therefore, the potential increased use by freight trains of the Metropolitan Avenue tunnel should be addressed.
The Port Authority of New York & New Jersey and the Federal Highway Administration completed a “Cross Harbor Freight Program, Tier 1, Final Environmental Impact Statement” (EIS) in September 2015.
The Tier 1 EIS selected two modes of cross harbor rail transportation for consideration in the Tier 2 study: enhancement of the existing car float operation or a new, two-track rail freight tunnel between New Jersey and Bay Ridge in Brooklyn. The Tier 1 EIS tunnel proposal included three operating scenarios, which make different assumptions concerning system wide operating characteristics, interchanging, and pricing schemes that might discourage or limit or encourage the amount of through traffic expected.
The figure below, extracted from Figure 5-8 in the EIS, indicates its assumption of four daily train movements on the Fremont Secondary (between the Oak Point and Fresh Pond Yards) if the car float service is not enhanced and the Cross Harbor tunnel is not built:
The figure below, extracted from Figure 5-13 of the EIS, indicates its assumption of between seven to twelve additional daily train movements on the Fremont Secondary if the Cross Harbor tunnel is built:
The total freight train movements per day projected at the Metropolitan Avenue tunnel are summarized in the table below, along with estimates of the time when freight trains would use one track in that tunnel:
Conclusion
There is no need, now or in the future, for a 2.9 billion dollar tunnel at Metropolitan Avenue or for street-running LRVs to avoid the existing tunnel there. Subway-type transit cars and freight trains can time-share the existing tunnel.
A copy of this paper, which includes additional endnotes identifying sources, is available here:
