King County Metro Proterra Catalyst

On February 17 Metro held a press event to announce that their three all-electric Proterra Catalyst battery-powered buses would be hitting the streets in revenue service that day. The buses will operate on routes 226 and 241—two routes that operate in a loop from the Eastgate Transit Center through downtown Bellevue.

Initially 4602 was entered service at Eastgate at 11:25 but it later broke down completely at Bel-Red Rd & 124 Av NE about an hour later. A diesel hybrid was brought in to replace it, and three hours later a mechanic brought out 4603 to run the rest of the trips for that run.

I rode route 241, and when it arrived at Eastgate TC it had used just 48% of its capacity after running a complete 18 mile loop of almost two hours. The layover time between these two trips is just 12 minutes. Since charging takes approximately 10 minutes and is required after every loop, this may mean that the trip will leave late if there are schedule delays on the incoming trip. Metro has not built in any additional layover padding next shakeup.

The “docking” process of the vehicle pulling in to the charger is almost completely automated; the operator simply holds the go pedal down and the bus takes care of forward acceleration. When the charge is complete, the arm automatically retracts.

The interior layout is designed to maximize seated capacity, with three seats being wedged in transversely between other rows of seats in order to make maximum use of space. The rear door is a passenger-activated plug door–the doors slide parallel to the body rather than pivoting. The rear section features a rear window and will soon be the only vehicles in the fleet to do so.

King County Metro Proterra Catalyst interior looking back

The entire interior of the bus is made of plastic (save for the seats and structural components of course) and despite this the bus was not squeaky on the inside (except for the sheet of Plexiglas near the rear door). Ride quality was neither stiff nor soft and is among the best ride quality I’ve experienced on a 40′ bus. Shifting was so smooth that only once did I question whether the bus had more than a single speed transmission (it has a 2-speed transmission, and Proterra claims this is why they have the best efficiency and acceleration of all EV buses). The whir of the electric motor wasn’t as quite as I had been expecting. Anecdotally I felt the interior volume was similar to the diesel artic I rode immediately after (sitting approximately the same distance from the engine compartment). The motor makes noise when braking—capturing energy for later reuse. While riders of a handful of Seattle routes are no strangers to having a silent bus when stopped, this is a relatively new experience for Eastside routes as only the trolleys and Metro’s newest hybrids have an engine shutoff feature.

Testing initially began last summer, and the buses have often been seen around Bellevue sans passengers but filled with water barrels to simulate a passenger load. This testing has purportedly gone well as Metro is seeking $3.3 million in additional grants to buy six more of these buses along with a second fast-charging station. Doing so would mean Metro could make this loop run solely on electric buses.

The video below has an interior view of the docking process as well as a ride along on route 241:

69 Replies to “Metro’s Battery-Powered Proterra Buses Now Running Revenue Service”

  1. Looks like the link to the video is missing. But in other news this is encouraging, I look forward to the day when mass transit no longer requires fossil fuels :)

  2. Thanks for doing the reporting and photography on this. I would love to see Skagit Transit get an electric bus for our Route 208 which serves our north-south trunk/spine between Skagit Station, Mount Vernon and Chuckanut Park & Ride, Burlington with many commerce opportunities. Having a smooth ride on this route can help recruit others to think transit first when travelling.

    1. If you want Skagitonians to ride more, take a cue from your friends up north and run it every 15 minutes.

      1. Donde;

        I agree. If I can get Skagit Transit to seek voter approval to use some of its banked sales tax authority, bus frequency is something that I would push for at that time. Looking at a 11/2018 vote most likely – getting a new planner now (old one was very good but had family crisis and didn’t want to live in the taxing district), it takes time to research and plan out such things and it’ll most certainly be a one shot or not affair.

  3. This is good news – thank you for the detailed report! (Proterra is located in my other “home town” of Greenville, SC, and they are excited to see how things go with Metro’s use of them in revenue service.)

    1. Proterra is expanding and now has a plant in the CA bay area. They are guessing, probably correctly, that west coast cities will be the early adopters.

      A news report I heard quoted Dow as saying he was going to mandate a shift to an all electric fleet. Anybody else hear that and have so knowledge of the source and it’s accuracy?

      Re: battery charge time of 10 min. and possible schedule delay because of layover. If the bus only used 1/2 it’s charge I would expect the charge time could be significantly less. They may want to maximize the time available for charging when there is a layover to extend battery life as “quick charging” tends to be hard on batteries.

      1. Constantine said Metro plans to have an “all green fleet” by 2018, not all electric. They define “all green” as electric and hybrid electric buses.

      2. Yes; actual implementation of this law is way behind for good reason. The requirement in state law is “to the extent practicable.” The relevant administrative rules have a couple of big exceptions including life-cycle cost and in-field charging. See the applicable WAC 194-28.

      3. If it takes 12 minutes to fully charge, it takes about 6 minutes to do half a charge.

        So, if the bus only used half its charge on the route, 10 minutes layover provides a 4 minute recovery time. I would probably schedule a slightly longer recovery time.

  4. I guess the initial rollout being on routes that are known for low ridership is a deliberate decision to minimize the impact to the public if something wrong. With the breakdown, I guess that was the right decision.

    It would be nice if battery-powered buses could make their way into higher-ridership corridors, eventually replacing the trolley routes in Seattle. This would allow an electrified 48 without the expense of installing additional trolley wire, as well as allow for an extension of the 13 to connect upper Queen Anne to Fremont.

    1. The routes were chosen because Metro only has one fast charger (besides whatever they have at the base), and they decided to install it at Eastgate P&R. They’re limited in what routes they can run these buses on because of that. You need a route that both terminates at Eastgate and doesn’t have an excesive roundtrip distance. The 271, for example, is 13.5 miles one-way, so the roundtrip distance to/from Eastgate exceeds the rated range of 23 miles.

      1. So how many routes can these buses be used on, anyway? Enough to be worth the bother of maintaining a new model of bus and several charging units?

      2. How costly is it to install fast chargers in the field? If each battery-powered route had a charger at both terminals, longer routes could be served. Like everything in new technology, the cost of chargers should come down over time; the quicker the better.

      3. The initial plan with the $4.7 million grant was 2 buses and 2 chargers. Instead they chose to go with 3 buses and 1 charger. So I would say the cost of a fast charger in the field is about a million.

      4. After watching the videos, it’s clear the current bus chargers are huge and undoubtedly expensive units. Let’s hope they shrink in size and cost, and do so quickly so they can be installed at more route terminals.

      5. The chargers aren’t going to get smaller; they’re very basic electrical equipment and the size is determined by electrical requirements. They could get cheaper if *economies of scale in manufacturing* apply — i.e. if a lot are being manufactured.

    2. It doesn’t make since to replace the electric trolleybuses with battery electric buses, at least not yet. The trolleybuses Metro just purchased should last at least 15 years with proper maintenance.

      The 48 will almost certainly be converted into a electric trolleybus route in the next few years. Part of the project to rebuild 23rd Ave is installing infrastructure to support trolleywire.

      1. Ricky, I don’t think anybody is planning to replace the trolleybuses anytime soon. These new buses look very promising, but considering how new this technology is, there will doubtless be years of working with them in service.

        I doubt I’m the only one looking forward to how the Proterra fleet can handle James Street uphill between Third and Harborview with a standing load.

        But if not, plenty of other routes for them ’til that gets taken care of.

        Mark Dublin

    3. I was on the 226 that broke down. It was already 15 minutes late when it stopped completely. FWIW there were approximately 20 people riding at that time. So not bad for midday in the suburbs. The process of throwing passengers off the bus could have gone a lot better. I imagine drivers don’t get to practice how to do that very often. It would have been nice to see some alternative route option information or a offer some help for the man getting to a next bus.
      I posted a photo on Twitter and Metro replied “@dukeofdensity yeah, looks like a glitch with a low voltage wire connection. Battery bus #2 took its place to work route.”

      Jeff T.

      1. Jeff, a driver with a hard time explaining needs some further training. Nobody is asking-I hope- passengers to analyze the hybrid system. Also, explanation problems are not confined to any propulsion mode.

        However, little trick not hard to learn. In the DSTT, for drivers and passengers alike. Whatever PA and signs say: do the opposite. Really: over come temptation to do that.


      2. Wow, 20 people on a 226 is a lot better than I would have expected. Could it have been one of those afternoon trips serving a high school that just let out?

    4. Why in the world would you want to replace the trolley routes? They have infinite range and greater hill-climbing power because they’re directly connected to the electrical distribution system. Yes, it’s expensive to maintain the overhead, and passing through intersections like 12th and Jackson can be slow depending on the route to be followed.

      But there is no more reliable rubber-tired transportation than an ETB. They are troopers.

      1. Anandakos, there’s a 50 mile long trolleybus line over the mountains in Crimea, part of Ukraine. Check out subject on you-tube. Notice that while fleet has some new buses, like much Russian equipment , coaches are old and look like they’ve seen a lot of service.

        Still think extending the Route 7 more or less eastbound from 62nd and Prentice to Ellensburg would be a good idea.


      2. Agreed. From a fundamental electrical efficiency point of view, directly-connected trolley buses are always more efficient than battery buses. This is due to electrical conversion losses when charging and drawing down the batteries.

        Trolley overhead wire has a construction and maintenance cost, however. When battery buses are commonplace, they will be used on lighter demand routes, while on more frequent routes the cost of the trolley overhead will be offset in operational electricity savings.

      3. There’s another consideration. Batteries can be charged off peak. Currently we turn off wind generation when hydro power exceeds demand. Having a source of stored energy would be able to absorb some of that power. Granted, a couple of buses aren’t going to make any difference but if there’s a large fleet of electric vehicles (like private cars or delivery vehicles) it starts to become significant. And quick change battery packs, like Tesla demonstrated is a competing technology to fast charge stations.

        Maintenance of the overhead is a big cost driver but the purchase cost of ETBs and their maintenance is also a consideration. Because there are so few trolley buses produced for the North American market they are essential custom built for every order which drives up the initial cost and makes parts availability an issue. The system is a whole lot more involved than “a couple of fiberglass poles.” There’s also the issue of ETBs not being able to pass without off wire capability which once you add it’s not much of a stretch to just lose the wire forever. Additionally you have to qualify a sub set of drivers to handle the ETB routes which is a whole additional skill set vs driving a “regular” bus.

      4. Running short distances off wire is a huge difference in capacity over an entire route.

        Line side batteries or capacitor systems would have even greater potential for evening out the grid as the capacity would not be limited.

        The robot battery changeout concept was something ebus was talking about in 2005 or so, Not sure if any city ordered one.

      5. Line side batteries are a big expense without any additional payback. If you’re going to manufacture the batteries it makes sense only if they are going to be used for a mobile application. For city transit buses off hour charging doesn’t really make sense since they make so many stops and layovers. But for delivery vehicles and personal vehicles it does.

        The easiest thing to do would be to incorporated pumped hydro storage of excess off hour capacity. Ideally you’d use pumping stations to replenish irrigation storage “up stream” but that requires a lot of infrastructure. Assuming the reservoirs have the capacity without jeopardizing flood control, as ridiculous as it seems the easiest thing to do is use the electricity to run giant pumps that recycle the water exiting the turbines back into the lake behind the damn dam. Maybe that would give us the capacity to shut down some of the coal burning plants sooner rather than later.

      6. Depends on how the demand charges are set up at the utility billing.

        Line side power storage has reduced the energy cost by 40% at a couple of the big metro operators.

      7. Because trolley lines are really really ugly. There’s no better way to making a city hard to look at then to run trolley lines everywhere.

        If you can be zero emissions without trolley lines why wouldn’t you do it?

      8. In the end you use more energy due to battery chemistry and having to move the weight of the batteries and it means limiting the length of each bus route.

        Besides, in some places the existing utilities are so tangled that trolley wire is hardly the only problem.

      9. Bernie, if you can only get 23 miles per-charged battery, and you manage to swap batteries each run instead of charging in-bus, you’ll still have to have a stockpile of batteries to actually get much of the charging done off-peak. Several times as many batteries as buses, and the batteries ain’t cheap.

      10. That’s why I said it’s not so relevant for transit buses but more for delivery trucks and personal vehicles. However, there are configurations that go 200 miles on a battery charge so those routes are candidates. Also peak hour only buses could at least do half their charging at night.

        I think ultimately (10 years or so out) most buses will be using supercapacitors rather than conventional batteries where charging is more like 30-90 seconds and no rare earth elements are required.

    5. From Eastgate, besides the 226/241 combo the 246 would be an option. The 245 is marginal but probably possible. The 212 is technically possible, but since it is a peak express with only a few in-service counter-peak trips, it seems like a waste.

      If you add more fast chargers you would expand the number of possible routes quite a bit, because in some cases you’d only need a one-way charge. Putting chargers at the major Eastside transit centers would do this. However one of the reasons Metro chose Eastgate TC is because they can locate the charger in an off-street layover location. Kirkland TC and Bellevue TC, for example, only have on-street layovers or in-bay layovers. I imagine over time Metro would become more comfortable with the charging system, but for now it is a restriction.

      1. Metro ran the bus to IDS during testing, so I don’t think the 212 is completely out of the question.

        The 340-series routes are a good candidate too, with the looping through Northgate. I doubt there will be any action there until after ST and Metro finish building the new TC with the opening of Northgate Link extension.

  5. Building charging stations at other eastside TC’s or P&R’s might be more difficult than it was at Eastgate. Eastgate has a lot of room and has that second layover area under the bridge. Other TC’s I’m visualizing are more compact and wouldn’t seem to have room for one. Kirkland TC? Bellevue TC? Where would a charging station go at those locations? Redmond might have the room for one. And from what I understand, the lane has to be somewhat protected so that a lost semi doesn’t take out the overhead.

    1. Good point, and good call on Redmond. Overlake TC would definitely have room for one, too; it could go on the east side of the loop near where the 244’s or 566’s lay over. I think Issaquah TC and Issaquah Highlands would have room, too, though I think most routes from there would be too long for this bus.

    2. They did run the bus, in test, to downtown Kirkland. I saw it once at any rate. They may be more risk-averse about doing that now it’s in revenue service.

  6. If Metro doesn’t add more layover time padding for these buses, this will be a doomed experiment, because the Proterra’s schedule will be much more unreliable than the diesel’s schedule.

    A diesel bus that’s running late and gets to its terminal with no recovery time can still leave on time for its next trip. The Proterra will have to leave at least 10 minutes late because it needs to charge.

    1. Not much loss, Sam. Since fare-boxes became main means of sabotage-well Stalin would have shot personnel for it- I mean collecting DSTT fares, Metro has long since been adding scheduled time to every Tunnel run.

      So this is one bridge which, unlike University and Montlake drawbridges, Proterra will not have to slow for special work or get stopped under dead spots. Thereby saving lost days, rather than minutes.



    Doubt Russian drivers have any problem explaining about getting off the bus.

    Wonder how long it takes to qualify on this route. But I can just imagine what your base chief will say if you de-wire!

    But also, any trouble for us about trolley wire spoiling views, we can offer an alternative. You know what they say: Four wires are better than two!

    But also shows how to handle rewiring without leaving seat. Also excellent way to keep three tons, or whatever, of 600 volt hardware from interfering with traffic if somebody throws a pole.

    And- overhead that makes above problem impossible, due to lack of poles. And greatest of all? Strip mine the size of Arizona can now be Environmental!


    1. If you’re referring to the artic I mentioned in the post it was one of the ST 9500s, so Detroit Diesel Series 50 and Allison B500R.

  8. Just remembered one thing. Checking out alternatives for DSTT propulsion long ago and in a galaxy far away, there was some consideration of finding a way to let buses charge batteries before entering the tunnel.

    Especially sad since Breda probably would not have been able to provide this. Too bad survival of the fittest only applies in retrospect, meaning what’s still here after it killed everybody else, including the ones that died of disgust.

    Considering how much time buses often sit in staging, could now probably make more than one round trip before a ten minute recharge is needed. Could be interesting experiment ’till full-rail these next couple of years- since no buses run on wire anyway.

    Also, technical development next few years might make this a no-brainer for a second dual-mode tunnel.


  9. Tim,since we’re talking transit, for all anything life-and-death controlled by computer, my first question would be:

    “Was whoever programmed this last qualified on intended route and run?”

    Next question:

    “Will the computer be able to decide whether to use newspaper or sand to cover up vomit on the floor, or deal with sanitary waste by choice of uselessly asking Control to pull the coach, or just telling (not explaining!) passengers to leave by the other door?”

    And finally: “Will computer irreparably disable the coach if Breda gets the contract? Not for failure to perform, but because sensors will never be able to distinguish above olfactory conditions smell of all previous Breda vehicles?”

    If not, all the best legal defense in the world will be able to keep Metro’s entire Risk Management department from being deported to Australia.

    And only allowed to come back when they’ve got enough Melbourne streetcars that Metro won’t ever be able to keep them out of service for ten years and give nine of them away.


      1. SEAN, computers themselves are valuable tools, creating a world of improvement. In the transit industry, and the medical profession, things are possible that save weight and complexity and also lives.

        While usual elderly suspects growl about kids online all the time-really down to two years old, fact is that children are visibly engaged in the adult world before they can talk. And reading before kindergarten.

        The real danger about them in applications like transit, besides suddenly failing with no warning, is that the accuracy of their every decision is only as good as the worst thing the worst informed human tells them on the worst day of his life.

        This was my point about automated buses- and even more, weapons. Everything above really happens, often at the same time, when the bus is the most crowded. So not that computers will never be able to handle these. But for a long while, it will be easier to train a human to perform things than to write them into a program.

        Now, Stalin. Think Hitler, killing many times more people in a many-times bigger country, trying to bring it a thousand years’ distance into the modern industrial world in twenty years.

        No excuses for things like this- no matter how apologists try to view them. Just very old photograph- the more accurate, the worse.

        Bad enough without a war. With one, managerial habit was that if a farmer driving a broken down locomotive had it fall apart on him, he’d be shot for sabotage.

        Only one very quiet echo here: it’s not unknown for workers to be blamed for events management should have fixed. Preventing things like these is what our politics should be for, and kept constantly under repair. Also labor unions.


  10. The seating is too much. The interior looks cramped. Some passengers prefer to stand.
    This is transit? Right? More standing room would have been welcomed. It’s not too late. Arranging for more standing room via removal of two-bys, or replacing two-bys with one-bys, would be welcomed. Please. Please. Especially near the exits.
    Some of routes in Rome are an example of where such arrangements of standing vs. seating are in alignment with social expectations, norms, and passenger volumes.

  11. I heard that 4602, which I believe was the same Proterra bus that broke down on Bel-Red road last week, broke down this morning in the charging station at Eastgate. And it was stuck there long enough that the other two Proterra’s, 4601 and 4603, arrived at Eastgate and weren’t able to charge for some time, and then when they finally could recharge, were very off-schedule.

    Can someone confirm this?

  12. So these buses have a range of 23 miles. Does anyone know the range of a typical Metro hybrid in local service? Obviously diesel and hybrid buses need to be refueled, too, but their range must be long enough that they can make a few round-trips before needing to refuel.

    Some of the delays mentioned in the main post and comments are really bad — riders really rely on schedules for not-so-frequent routes! It sounds like we’re going to need technological improvements or new operational strategies before deploying these buses more widely.

    1. The hybrids have 100 gallon fuel tanks I believe, so figure a range of between 300-400 miles (3-4 miles per gallon), which is more than sufficient for a day’s worth of service. The 226/241 combo that 4603 is running today is no more than 200 miles. A longer route would necessarily make fewer total runs, limiting the total distance traveled. Some of the longer ST Express routes like the 512, 545, or 590 which run all day may rack up the miles, but they’re on the freeway a lot where fuel economy is a bit higher. I imagine range is not an issue for diesel or hybrid buses in general.

  13. I’m wary of early adoption on this kind of tech – rapid charging is difficult to do without damaging batteries, operations need to be adjusted (as much discussed here) with extra schedule padding for charging, and we don’t have a good picture of long term reliability yet. However, there is this:

    Pretty compelling, 4x fuel economy. And it’s probably be a good thing if Metro gets good at adjusting operations for battery busses early. But I hope we still treat battery powered busses as a trial until we’ve got the operations kinks worked out and the manufacturers have a bit more of their kinks worked out. Long term, though, this is going to be awesome.

  14. While I support the use of battery buses, it is important to appreciate that they are no panacea and they should not be seen as a replacement for trolleybuses. I’d rather see a policy of using both types of vehicle . And why not get economies of scale by having a vehicle that can be both battery and trolley?

    Unfortunately these sort of articles fail to mention any facts and rely on “spin”. Do the people who comment here never use any numbers or statistics in their day time jobs?

    1. Battery buses are much heavier than trolleybuses and this tends to restrict the legal passenger load and the energy efficiency.
    2. To be more specific on energy efficiency, a paper publish by the Zurich Institute for transport planning produced a lot of data for various forms of motive power and stated that a trolleybus was 17% more energy efficient than the same sized battery bus.
    3. A normal trolleybus or diesel bus on an urban stopping service can run up to 250 miles a day. I suspect the range of these EVs is far lower than this. The article mentions 18 miles in two hours. How reliable and full will these rapid recharges be? Or will the charge level gradually run down during the day, requiring a much longer layover to “catch up”?

    4. The fast chargers don’t come free. A high proportion of the cost of electrifying a trolleybus route is in the form of distribution feeders, substations,, transformers etc. While the battery buses don’t need the overhead running wires, they still need the rest of the heavy duty electrical kit. Per km how much is required to equip a route with chargers as opposed to full trolleybus equipment? I would not be surprised if the cost is at least 50% of the trolleybus equivalent.
    5.Other contributors have already mentioned that a trolleybus can really draw juice when it needs it. A battery bus simply would not be able to compete with a trolley going up Queen Anne.
    6. Batteries have a limited life cycle plus diminishing performance over time. Be ready for very expensive battery replacement after about 5 years.

    I am not trying to do a hatchet job. There could well be a role for battery buses on lighter routes. And why not have bigger batteries on trolleys to allow them to branch off onto unwired sections? But don’t think the trolleybus is being surpassed without studying the engineering facts.

    1. Unfortunately these sort of articles fail to mention any facts and rely on “spin”. Do the people who comment here never use any numbers or statistics in their day time jobs?

      1. Battery buses are much heavier than trolleybuses and this tends to restrict the legal passenger load and the energy efficiency.

      I came up with this for a google search on “proterra curb weight“:

      With a curb weight of only 27,370 lbs., the Proterra Catalyst is not only lighter than any other electric bus, leading to greater efficiency, but is also more durable than buses made of aluminum or steel and less prone to corrosion.Jun 10, 2015

      Best spec I can find for a Diesel Hybrid, and that’s what Metro would order in lew of an all electric, is CURB WEIGHT: 31,220 lb for and ORION VII DIESEL-ELECTRIC HYBRID BUS.

      According to SF Muni:

      Technical Specifications of New 40-foot Standard Trolley Coaches.
      Vehicle Weight: approximately 31,500 pounds.

      The overhead trolley mechanism isn’t light and requires substantial reinforcement to the body and roof which adds additional wieght (and cost). Then to go off wire a battery and all the attendent switching mechanism has to be added. The trolley contacts are hardly a perfect conductor and the friction of the shoe and all the moving parts also create an energy hit as well as additional maintenance.

      1. Proterra’s buses are light compared to other battery buses because they have small batteries — 23 mile range between recharging. BYD and New Flyer both decided to offer larger batteries — longer range between recharging.

      2. Even the BYD buses aren’t any heavier than a diesel hybrid of the same size. Lighter if you add a full load of diesel (200 gal. = 1500#). The weight argument against electric only buses doesn’t stand up to scrutiny; even against trolley buses.

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