Why is New Mexico’s Rail Runner So Slow?
The United States is seeing a growing interest in expanded and improved passenger rail service across the country, and New Mexico is no exception. What is exceptional about New Mexico is that we are one of the few states in the country — and the least populous — that already has commuter rail service. Our Rail Runner primarily connects two of the state’s three primary metro areas, Albuquerque and Santa Fe (Las Cruces being the third), providing service to the communities and pueblos along its path and also to Belén, a southern suburb of Albuquerque. Also important to know is that the doors of the Rail Runner make the Looney Tunes Roadrunner “meep meep” sound when they close.
With a substantial budgetary windfall from the state’s natural gas sector, the New Mexico legislature is considering enhancing passenger rail in the state. Led by a legislator from Las Cruces — the one primary metro area in the state that does not have rail service — legislators are considering a proposal to build a high-speed line that would not only connect Las Cruces and Albuquerque, but likely extend to Denver, El Paso, and possibly Chihuahua as well.
That the state is considering a “high speed” line is notable for a few reasons. First, high-speed rail is amazing, and we should definitely do it. New Mexico’s connections to the rest of the country include interstates 10, 25, and 40, which due to high and mountainous terrain can be dangerous to traverse in the winter and are expensive to maintain; and the Albuquerque Sunport and El Paso International Airport, neither of which are particularly large. December 2022 saw a classic example of how fragile our connections are: wintry weather made the 40 dangerous in the northwest; a jackknifed semi blocked the 25 north of Albuquerque; and 40% of the Sunport’s traffic belongs to Southwest Airlines, which had canceled the large portion of their flights. The only reliable transportation out of Albuquerque to the north or west for a time was via train: the Rail Runner and Amtrak’s Southwest Chief.
But second, and what I want to focus on in this article, is that the emphasis on “high-speed” also highlights one of the main issues with the Rail Runner. While a car trip between the downtowns of Albuquerque and Santa Fe generally takes a little less than an hour, the Rail Runner makes the 66 miles trip in 1:40, substantially slower. Understanding why this occurs is crucial not only to improving Rail Runner service but also to ensuring that future high-speed service lives up to its potential.
The Rail Runner has a top speed of 80 mph, which is both how fast the locomotive and cabin cars are rated to go and how fast the tracks allow. This speed is also achieved for a good portion of the route: the Rail Runner exceeds 75 mph on just under half of the route and exceeds 60 mph on about two-thirds of it. This is not a mandatory speed cap, however. Amtrak’s nearby Southwest Chief reaches 90 mph for stretches in northwest New Mexico, and Maryland’s MARC commuter train can even reach 125 mph between Baltimore and DC.
So, how much does this speed cap hurt the Rail Runner? As it turns out, this is not the main source of time loss. Indeed, while about 43 of the Rail Runner’s 66 miles are spent above 60 mph, only 34 of the 100 trip minutes are at that speed — after all, the miles go by faster at higher speeds. This reveals an immediate problem: raising the 80 mph speed cap alone can only save at most 34 minutes on a trip that is 40 minutes too slow. If the Rail Runner went 160 mph everywhere it went at least 60 mph, the trip would still take at least 1:20!
To find where the additional time loss is coming from, let’s look at the data! One of my favorite tricks is to examine the plot of pace (min/mile) vs distance when analyzing trips. While plotting speed (mph) vs distance is common — it is the default view on Strava — the benefit of a pace plot is that the area under the curve, being minutes per mile times miles, represents the trip duration. We can then look at the plot to see what the main contributions to the area — or trip time — are.
Immediately obvious in this plot are the train’s stops: the train stops 3 times in Santa Fe (left), twice in Albuquerque (right; including departure and arrival), and 6 times between the two; while the stops in Santa Fe and Albuquerque are somewhat indiscernible, the remaining six stick out prominently.
That the Rail Runner stops six times between the Albuquerque and Santa Fe areas is a fairly large source of time loss. Those six stops together force the Rail Runner to drop below its 75 mph “cruising” speed for over 17 miles and 40 minutes, of which only a bit under 9 minutes are spent actually stopped across the six stations. This is also a good time to point out that even though Santa Fe is about a half mile higher in elevation than Albuquerque, I’m analyzing the downhill route. For what it’s worth, it does not appear that the uphill behavior is any different.
At a speed of 80 mph the Rail Runner could traverse that 17 miles in 13 minutes, meaning that each of those six stops costs about 4.5 minutes of travel time. A top speed of 110 mph — the maximum speed for which road crossings are allowed — increases the cost of each stop to a bit over 5 minutes.
Interestingly, there is an express Rail Runner trip, which removes five stops from the itinerary: one in Albuquerque, one in Santa Fe, and three of the six intermediate ones. Curiously, this “express” route only saves about 13 minutes over the full-service one, saving 2.6 minutes per stop. What’s the deal there?
If we look at the speed graph for the Rail Runner around the somewhat-urban Bernalillo stop, we immediately see the issue (aside from needing to stop twice): while the train can fairly easily accelerate out of the town, it must spend about a mile before the stop traveling around 30 mph. The true cost of the intermediate stops — at least those in populated areas rather than park-and-rides — is not dependent on the train’s top speed. Replacing the stops with a minimum of 30 mph saves 3.3 minutes per stop, not too far off from the true value.
This raises a rather conspicuous point, that has been an elephant in the room for this entire discussion. If the barely-urban Bernalillo station has such a strong effect on the trip duration, what about the train’s stints in the much larger Albuquerque and Santa Fe?
Within the bigger cities, the Rail Runner is slowed dramatically. In Albuquerque, the train is kept at 20 mph for nearly two miles, although it does get to reach 50 mph for about a mile between the northern Montano stop and downtown; the average moving speed over the five miles the train spends in the city is 25 mph. Up north, the situation is significantly worse. Not only does the Rail Runner stop three times within Santa Fe, but it is also stuck at 30 mph for the entire stretch. Here, the Rail Runner’s average moving speed is only 22 mph over the six miles it spends in Santa Fe.
Combined, the Rail Runner spends nearly 30 minutes in Albuquerque and Santa Fe, only 3 of which are spent stopped. It’s actually somewhat remarkable how bad this is: in Albuquerque, the Rail Runner runs approximately parallel to 2nd Street NW, which has a speed limit of 40, but the commuter train with a seating capacity of 300 is limited to 20. In Santa Fe the tracks go between Cerrillos Road to the west and NM 285 to the east, both with speed limits of 35 mph.
A high-speed connection between Albuquerque and our neighbors would be transformational for the state, but we should recognize that top speed isn’t everything. Each mile we upgrade from 20 to 40 mph has the same effect on trip times as upgrading a mile from 80 to 160 mph. It would be a tragedy if a fledgling New Mexican high-speed rail system were hamstrung by the same speed restrictions facing the Rail Runner, and such a missed opportunity if we built the infrastructure for a new system while leaving the Rail Runner in the dust.