Despite the frustration I experience while planning a HSR line across the Bay State, I've attempted to tackle the Big Kahuna: the southern Northeast Corridor. This 225 mile line is the busiest in the country. Naturally, it has many important stations: New York (number 1 busiest in the country), Washington (2), Philadelphia (3), Baltimore (8), Wilmington (11), Newark (13), BWI Airport (15), and Trenton (24). Amtrak's Acela Express trains stop at each of those stations (though not all individual trains do) plus Metropark in New Jersey. Amtrak's Northeast Regional trains stop at an additional 8 stations, and the various commuter rail operations serve at least 40 more. The line has a very long history: part of the line runs over the oldest operating railroad bridge in the world, built in 1836. The most recent major change to the line is the electrification between Washington and Baltimore, which was completed in the late 1930's.
Theoretically, Acela trainsets can reach 165 miles per hour, but due to a number of constraints the average speed for a trip from DC to NYC is just 78mph. The trip currently takes 2hr 47min with 4 intermediate stops, and 2hr 52min with 6 intermediate stops. The magic number people want to achieve for DC-NYC travel time is 2hr 30min, which would mean an average speed of 90mph. To cut the journey by a further 30min to 2hr, the average speed would have to reach 112mph, a 40% increase over the current figure.
I experimented with a few sections of entirely new track, which turned out to be pointless. Building a 25 mile stretch of HSR track between Washington and Baltimore would cut travel time by only 10 minutes. That doesn't seem like a good way to spend $1.25B, which is what the new segment might cost. And trains would still have to crawl through the Baltimore and Potomac Tunnel. Creating a new line east of the Delaware was the only way to lay new track north of Wilmington. It would be very expensive and somewhat useless because it would bypass so many busy stations. Elsewhere, sprawl made a new line completely impossible.
The inability to plan a new line meant that incremental improvements would have to be the means for reducing travel time. Amtrak and its supporters have been arguing for more capital investment in existing NEC infrastructure for decades, but the funds allocated by Congress have been minimal. Below are the improvements I would suggest, in rough priority, based on reading a number of reports, reviewing track diagrams, and eyeballing aerial photographs. The four cost levels correspond to guestimates of <250M, $250M-$1B, $1-3B, and >$3B;.
- West Baltimore tunnels - The B&P Tunnel for passengers and the Howard Street Tunnel for freight are the biggest choke point in the entire corridor. They both need to be replaced for reasons that are very well explained here and here. Cost: high. Benefit: high.
- Catenary - The power system south of NYC is unique, and not in a good way. It supplies 11kV, 25Hz AC electricity, which is used nowhere else in the world. The configuration of the wires themselves limits top speeds to 135mph. The entire system between NYC and DC needs to be replaced for those two reasons, and general age. Cost: moderate. Benefit: high.
- Signaling -
The current signaling system is sufficient, but higher densities (meaning shorter blocks) on the entire line would increase capacity. Cost: moderate. Benefit: moderate.Update 9/26: Amtrak has already installed a Positive Train Control system on its equipment, and plans to have all commuter and freight rail upgraded in the next few years.
- New Jersey flyovers - Northbound commuter trains entering the corridor from two branch lines in central New Jersey (one is just a stub, really) have to cross the two southbound tracks and the northbound express track before continuing. This creates safety and scheduling issues that should be eliminated. Cost: low. Benefit: low.
- Curve straightening - There are a number of areas where curves could be eliminated. In most locations, doing so would reduce travel time a small amount (15-30 seconds or so) and at the same time would increase passenger comfort and eliminate higher wear curved track. Cost: low (each). Benefit: low (each).
- West Delaware track and curve - From Wilmington south to Newark there is a section of the line with only three tracks. Newark is the southern terminus of the SEPTA commuter rail system, so adding track would reduce scheduling conflicts. There is also a curve on the section that could be eliminated. This work could be done in conjunction with the bypass below. Cost: low. Benefit: low.
- East Baltimore tunnels - The two relatively short bores of the Union Tunnel east of Baltimore's Penn Station have a total of only three tracks, and need to be rebuilt due to age and height issues. Cost: high. Benefit: low.
- North New Jersey bridges - Two movable bridges just north of Newark need to replaced. Cost: high. Benefit: moderate.
- Northern Maryland bridges and track - Between Baltimore and the Delaware state line there are three two-track bridges in an area with only three tracks. New bridges need to be added for capacity reasons, and the originals eventually replaced, and another track added to help fully utilize the new capacity. Cost: high. Benefit: moderate.
- Central Maryland track additions - Most of the segment between Baltimore and DC has only three tracks. Another track would add capacity. Cost: moderate. Benefit: low.
- Wilmington bypass - The Wilmington station is in a very constrained area, has only three tracks, and is bounded by sharp curves at both ends. The solution here would be to bypass downtown Wilmington with two high-speed tracks. The existing track would remain, but through traffic would zoom on by. Cost: high. Benefit: low.
- North Jersey track additions - A short section of track from just south of Elizabeth north to Newark Airport narrows down from 6 tracks to 4. More tracks would help scheduling in a busy area, but the construction would be difficult due to the surrounding area of dense urban development. Two curves could be eliminated as well. Cost: moderate. Benefit: low.
- Northern Jersey viaduct - This 10 mile long structure from south of the Newark airport to near the Hudson tunnels entrances would bypass three stations (Secaucus Junction, Newark Penn, and Newark Airport), two movable bridges, and a rail yard. Cost: extreme. Benefit: low.
- 30th Street Station approaches - The track and switches on either side of the main Philadelphia station are a mess. Consensus opinion is that the situation needs to be addressed, but I have no idea about how large of an undertaking it would be. Cost: ? Benefit: ?
I think completing items 1, 2, 5, and 6 would shave 15 minutes off the trip. Items 3, 4, and 10 might save some time, but most likely they would just allow for more trains to be scheduled. But increased service frequency is a worthwhile goal, too, especially for the commuter rail systems. Items 8 and 9 might save 2 minute each, but the main purpose for undertaking them would be end-of-life replacement of the existing infrastructure. Item 7 is another project that is important due to age, though the time benefit would be negligible.
Completing tasks 1-10 would bring travel time to 2hr 25min. Not bad. Amtrak experimented with a limited service Acela train, which had only one intermediate stop at Philadelphia. The journey time on the offering was 10 minutes faster than regular Acela service. Completing item 11 would allow for another intermediate stop at Baltimore without changing the travel time. The rest of the projects - items 12, 13, and 14 - might wring a few more minutes out of the journey time, but 2hrs 15min for a limited service train would be pretty good. Northeast Regional trains would benefit, too, though the amount would be less because the catenary upgrades wouldn't change their top operating speed.