Kids have a natural love of trains — from Lionel to Thomas the Train, it’s fun to drive or push the locomotives around the tracks and imagine the joy of traveling the open rails. If only it were so easy for adults. Out in the real world, operating a train system and network of tracks is a massive undertaking, a 24-hour-a-day job where the workplace is spread over hundreds and even thousands of miles.
One critically important maintenance task that passengers probably seldom pause to consider is tree clearing. Keeping the rights-of-way along tracks open is absolutely essential to protecting the complex grid of electrical lines that power trains, as well as ensuring that downed trees and limbs pose no threat to the trains themselves.
One of the busiest areas of train travel in the country is the Northeast Corridor, primarily from Washington, D.C. to Boston, where Amtrak owns and operates some 363 miles of train service. Add in branch tracks, and then consider that both sides of the tracks need to be cleared, and the result is about 1,200 miles to keep clear of trees just in the Northeast. Amtrak reports that this span represents “one of the busiest, most complex, technically advanced track structures in the world, with over 2,000 trains on Amtrak-controlled segments each weekday, including slow freight trains traveling at speeds of 30 to 50 mph [and] commuter trains that travel at speeds up to 125 mph.”
With this much traffic and the speeds involved, it’s easy to see why Amtrak is so devoted to tree clearing. “From a wire standpoint, the outages that trees can cause are very disruptive to train service,” explains Robert Verhelle, deputy chief engineer of electric traction with Amtrak. In addition to costly damage to lines or conductors, falling trees can also cause disruptions to service while crews are clearing the debris and repairing equipment.
While the voltages and exact positioning of the electrical system varies by location, there are typically three different line systems running beside and above the train tracks. For example, on Amtrak’s tracks from Washington to New York, a 138,000-volt transmission line runs atop the poles. Below that is a 6,900-volt signal line that powers signals along rights-of-way. Finally, there is a 12,000-volt “catenary” line that actually propels the electric trains.
Even if it misses the electrical lines, a downed tree still poses a danger. “It can damage equipment on the locomotive. In one case, we had a tree branch that shattered a windshield,” says Verhelle.
John Pielli, senior director of track maintenance with Amtrak, recalls another incident when a train struck a downed tree, which then damaged adjacent power poles and tangled the overhead electrical lines.
Such events happen infrequently largely because of the emphasis Amtrak places on keeping the area around tracks clear of trees. “We have a toolbox of different strategies to address, on a program basis, the dangerous trees that need to be cleared,” Pielli explains. For instance, there are a variety of strategies for determining what sections to prioritize for tree clearing. As one example, the track department communicates with the electrical department to determine where the most breaker trippings are occurring. “That may indicate trees are periodically touching the wires during high periods of wind. We’ll use that information as part of the formula for [determining] where we’re going to cut next,” he states.
They also fly over tracks using a helicopter equipped with Light Detection and Ranging (LIDAR) technology, which helps to identify areas where trees may be encroaching on wires. Because this aerial view can sometimes skew perspectives (“From 1,000 feet up, a 4-foot-high bush might look like it’s reaching out and touching the transmission line,” says Pielli), Amtrak also reviews video footage shot from a special track inspection car to get a more horizontal look at any sections that might need tree-clearing attention.
The clearance swath in the Northeast Corridor typically extends out 30 feet from the near rail and 15 feet around transmission lines, which may run above the track or be cantilevered out above the parallel access road. “From the height of the transmission line, we cut the trees back at 110 degrees. That way, if we had a 30-foot tree fall, it would fall short of the wire,” explains Pielli.
Federal regulations also dictate the need to control trees and vegetation along tracks because engineers operating the trains must be able to see trackside signals, crossing and upcoming station stops as the train is traveling. Amtrak’s goal in clearing a swath along the tracks is generally to do the job in such a way that each area can go five years without needing a trim cut.
Both Pielli and Verhelle stress that no two sections of track are exactly the same. From the placement and type of poles and electrical lines to the terrain and location of access points, Amtrak must look at all of the characteristics of a given section of track before determining what tree clearing approach(es) will work best.
Currently, about 25 percent of tree clearing work is handled in-house by Amtrak’s own internal crews, and 75 percent of the work is done by outside contractors. “Right now we have six contract crews working on the Northeast Corridor, and two of our own crews,” says Pielli.
He explains that contractors are chosen based on the specific approach required to clear each section of track: “We might have an area where we need them to climb for a mile or so; and then we might have an area where we need a bucket truck that reaches up to 75 feet; and then we might have another area where they can use a standard bucket truck and just cut along the right-of-way.”
All of the contractors that work on Amtrak property must modify their equipment with a physical stop to prevent random swinging of booms or movement of the turntables on their equipment so that trains can operate on the adjacent tracks at scheduled speeds, says Pielli. This is just one safety measure that allows tree-clearing crews to get the job done without disrupting or endangering train service.
“Our marching orders are to cut trees with as little impact to the operation as possible,” says Pielli. That’s a constant challenge, because tree work along the tracks often requires the catenary system that powers the trains to be shut down as crews work.
“Utilities do a lot of live line work in clearing their transmission lines, whereas our rules don’t allow that,” explains Verhelle, whose responsibilities focus on these electric lines. “We have to de-energize a circuit if the contractor is going to come within 15 feet of the transmission conductor or 3 feet of a catenary conductor. Turning a catenary circuit off during the day is difficult because we run a lot of trains.” (In some cases when tree clearing crews are working close to the track, right-of-way protection personnel are also required to warn workers when a train is coming.)
To minimize disruption to service, some tree clearing work is done at night. But, for the most part, this goal is met by selecting the right approach (“the right tool from the toolbox,” likens Pielli) to clear trees in each given situation. Amtrak has seven different “levels,” depending on the circumstances. This might mean sending in a small bucket truck and chipper; it might mean using a 75-foot bucket truck and chipper to get taller trees; it might mean using more mechanized cutting equipment such as feller-bunchers.
In the past, Amtrak typically contracted out mechanical cutting work. But a few years ago, the organization purchased its own fleet of heavy forestry equipment. Pielli says that this new equipment has produced tremendous results, but he also credits Amtrak internal track maintenance crews — headed by Robert McKinley — for quickly learning to operate the heavy machinery and use it to dramatically improve efficiency and productivity. “Their work is outstanding,” Pielli states. “Since 2009 we’ve cut 223 miles of trees.”
A great deal of thought went into determining the best types of equipment to use in clearing the often narrow and rough swaths alongside the train tracks. “Heavy forestry equipment is very rugged and robust. It was our thought to introduce that kind of equipment in the Northeast Corridor, where we have some challenges working in narrow areas,” says Pielli. “Tigercat was outstanding with their equipment and warranties and life cycles; we highly recommend their equipment. That purchase alone was a $4.5 million investment in our own rugged tree cutting and tree removal equipment.”
This included feller-bunchers, skidders and two self-feeding chippers. “They can chip a tree that’s 15 inches in diameter and there is no human feeding the machine. The skidder drags the trees just short of the chipper, and the chipper has a hydraulic boom similar to a grapple truck and it feeds itself, so it reduces the chance of human injury,” Pielli explains.
If the land alongside the track has a good downward slope, the chips are spread. In cases where there are ditches and banks rising up on the sides of the track, the chips are removed to ensure drainage isn’t impeded. (Emerald ash borer has posed another challenge for Amtrak’s tree clearing crews. Infected trees can’t be chipped, but instead must be packed up, brought to a staging area, and then trucked to an incinerator.)
Pielli says Amtrak specified and purchased Tigercat’s tracked feller-bunchers. “That way we’re not held back by rough terrain,” he explains. “And our choice was to equip them with tree shears rather than buzz saws. The machine grabs the tree and a big scissor can shear a 15-inch tree in three seconds. The shear allows the feller-buncher to reach up 20 feet into the air and ‘nip’ the top off; so it nibbles the tree down.” With tracks and electrical lines running close by, this added control is very important, Pielli adds.
When trees are too tall even for the feller-buncher, Amtrak utilizes another tool from its toolbox: “If we have a huge tree or a tree that’s in the catenary system, we leave that till an off-peak time,” says Pielli. “Our crews usually clear about one quarter mile per week. After we get 2 or 3 miles done, we come back to get those large trees, usually with a contracted crew of tree climbers. They’ll top the tree to a point where we’re comfortable using our feller-buncher tree shear.”
Tracks along the Northeast Corridor run through many populated areas and tend to be narrow by nature, making it all the more critical that encroaching trees are addressed, he adds. Unlike electrical transmission lines that often run through rural stretches of open land, there are frequently residential homes, parks, schools, etc., located beside these train tracks.
Pielli says that Amtrak makes a constant effort to meet with and work with neighboring property owners and communities, who sometimes are impacted by tree clearing jobs. This includes written communication and meetings to explain why trees are being cut. “This way they understand where we’re going to be and where we’re going to be cutting. We use bright pink or bright orange flagging tape to show where we’re going to be cutting trees, and you might be surprised how many people come out to walk those lines,” he explains. In many cases this precutting effort is able to put nearby property owners at ease and greatly reduces complaints that might arise if crews simply showed up and started cutting trees, he adds.
In some cases, Amtrak will replant vegetation, which helps from aesthetic and noise-control perspectives. “We’re aware the trains are loud, so particularly in very narrow, tight areas we may replant low-growing shrubs,” says Pielli. Even in cases where there is no replanting, the areas along the track look much cleaner. All of the tree debris is chipped and spread out or removed, and crews are cleaning up trash as they work, so the right-of-way benefits from improved appearance. Of course, most importantly, the tree clearing work allows trains to continue running safely and reliably — even in the real world.