Big Boy

Started: 2026-04-19 20:01:41

Submitted: 2026-04-19 22:53:02

Visibility: World-readable

Taking the train to Roseville to see the world's largest steam engine

Union Pacific embarked on a tour of their last operational instance of the world's largest steam engine, affectionally nicknamed "Big Boy", including a stop at Roseville at the beginning of April. This is just barely close enough that I could consider a day-trip to see it.

If traffic cooperated, I could have driven to Roseville in about 2.5 hours from home. But my first rule of driving in the Bay Area, especially heading north or east from the Santa Clara Valley along I-680 or I-80 towards the exurbs in the Central Valley, is to never assume that traffic will cooperate. It seemed somehow wrong to drive to go see a train, so I looked for alternatives. Roseville is on the Union Pacific mainline, on the long descent down from Donner Pass to the original terminus of the trans-continental railroad in Sacramento. It's served by one train per day on the Capitol Corridor, starting in San Jose and traveling all the way through Sacramento to Roseville, but the train times didn't line up with when I wanted to travel. There was a connecting bus offered on several trips per day, but according to the timetable this involved waiting in Sacramento for an hour. (And because the bus was subject to local traffic, for some trips it was timetabled to take 50 minutes to go a few miles down the highway, a journey that would take 30 minutes by train.) Google Maps offered to stitch together a tortured route involving three separate transit agencies (Sacramento Valley light-rail, Placer County transit, Roseville city transit). I figured it was probably close enough that I ought to be able to rely on Lyft but that too felt weird to take the train most of the way then cheat with a car.

I had one more option to get to Roseville from the Bay Area: from Emeryville I could catch the first two hours of the California Zephyr on its two-and-a-half-day trip to Chicago. The outbound trip left first thing in the morning; the return trip stopped in Roseville early in the afternoon and pulled into Emeryville late in the afternoon. This was the key I needed to unlock the whole trip. Julian and Kiesa decided to come along so I bought three round-trip train tickets to Roseville.

The California Zephyr departs Emeryville at 08:25. To get there in time (and attend to the logistics of parking, allowing for traffic over the mountain and along the way) we left home before 07:00. It had been raining on Friday, our first rain in weeks in an uncharacteristically dry winter; by Saturday morning the rain had stopped but highway 17 was still wet heading over the Santa Cruz Mountains into the Santa Clara Valley. Traffic was good heading up the East Bay to Emeryville; we arrived at the station with enough time to board the train and find our seats without being rushed before the train departed.

We rode in coach seats on the upper level of the first coach car, right behind the lounge car. The seats were large and comfortable, with ample seat pitch (so much so that it felt like there was wasted space). On a domestic flight this would be sold as a first-class seat. I wasn't ready to sign up to ride this seat 52 hours to Chicago, but it did feel almost plausible to do so.

Between Emeryville and Sacramento the train follows the same route as the Capitol Corridor, which I've ridden several times before (most recently a few weeks earlier) so I'm familiar with the route and the scenery along the way. The long-distance train makes fewer stops along the way than the corridor train. The best feature of the long-distance train was the Superliner lounge car; once we were underway I walked forward one car, got a coffee and snack on the snack bar on the lower level, and sat in a lounge seat to watch the scenery of San Pablo Bay and Carquinez Strait and the sugar factory at Crocket under the bridges (the well-maintained century-old brick factory contrasting with the newer industrial buildings next door on the tiny site constrained by the tracks and the water and the bridges). Riding in the lounge car gave me the chance to look up and see the steel truss structure of the railroad bridge connecting Martinez and Benicia, a view that's normally difficult to get looking straight outside the windows of a train carriage.

When we reached Sacramento the train filled up, and when we reached Roseville the conductor told us on the PA that 40 people would be getting off the train. (The normal seating capacity of a Superliner coach is 74 people. My train had two coaches so if we were all riding in the coaches it would have been more than one-quarter the capacity of the entire train. There were only a few people left on the upper level of my coach when we disembarked.) On our way into Roseville the tracks passed a major Union Pacific depot, with what looked like miles of freight sorting yards and locomotive maintenance and everything a major Class I railroad would need to operate.

We found the pedestrian walkway below the tracks and walked through old town Roseville, where the street grid aligned to the railroad tracks, to the entrance where we could view the train, parked on a siding next to the tracks. The massive locomotive was parked facing north-east, towards Donner Pass, painted glossy black, at the head of a long train of canary yellow Union Pacific railcars. There was a huge crowd of people clustered around the engine, trying to avoid a large puddle while jostling for the best view of the train.

I made my way though to the front of the train, pushing through a chokepoint formed by an awkwardly-placed puddle next to a temporary awning sheltering a couple of chairs and a sign giving some context on the train we were seeing.

With some patience I could advance through the crowd, as people satisfied their own curiosity and gave room for people behind them. I crowded up to the fence set up next to the engine and

From this angle it's hard to grasp the scale of the engine, or see the twin drive wheels that make it special. Steam locomotives are generally built with small lead wheels at the front of the engine, a set of driving wheels directly coupled together powered by the steam pistons, and another set of trailing wheels under the driving cab. At a first approximation, more drive wheels corresponds to a more powerful engine; and larger drive wheels means a faster engine. But there's a trade-off where adding more drive wheels increases the minimum turning radius because the drive wheels are coupled together. This locomotive was built with two sets of driving wheels, independently articulated for a better turning radius, each with four wheels on each side, doubling the power of the locomotive. It's a 4-8-8-4 engine; the biggest steam engine ever built; and the last of its kind.

I inched my way through the crowd to get a better look at the locomotive's drive train. Standing at the crowd-control fence I could see the front drive wheels up close, but even with my wide-angle lens I was too close to . (There was no good viewing platform in the crowd; if I got too far back people in the way would obstruct my view of the wheels. But this was part of the experience: standing in a crowd with hundreds of people willing to spend a Saturday on a siding in Roseville looking at an engineering marvel.)

Here we see three of the four drive wheels in the first set. There was another wheel just out of view, and another set of drive wheels just behind, followed by the driving cab and several tenders (holding the oil that fueled the boilers, and the water boiled for steam to power the pistons) and the rest of the train.

I took a selfie with Big Boy; then pushed my way out of the crowd to see the rest of the train.

Behind Big Boy were two diesel locomotives, numbered 1616 "Abraham Lincoln" and 1776 with a large novelty American Flag painted on the side celebrating the 250th anniversary of the Declaration of Independence. (As a major American corporation, Union Pacific is not above indulging a bit of nationalism when it serves their interests.) The rest of the train was a collection of rail cars restored to serve as a rolling reception train (there were a bunch of private events with Union Pacific staff on the train's schedule), including dome car #7015, formerly in service on the scenic passenger routes in the American West.

We waited in line for a walk through the "Union Pacific Experience", a boxcar set up as a small museum with a bunch of posters and exhibits talking about the history of Union Pacific; the modern railroad company is the successor to the companies that built the original trans-continental railroad in the nineteenth century. None of the exhibits in the "experience" were ground-breaking but it was interesting to see how the company presented itself.

At the far end of the train was an exhibit with a real working crossing guard with the covers open so we could see the machinery inside (a modest-sized electric motor with gears connecting it to the counter-balanced crossing guard, and position feedback so the controller could tell what position the crossing guard was in) and the controls that ran the crossing guard. There was a switch to raise and lower the crossing guard, which was fun; but I was more interested in the controllers, including the indicator LEDs that showed that the controller itself was indicating when each of the two lights in the crossing guard would blink to indicate an approaching train.

This line wasn't especially long but it ran slowly because there were a couple of railroad employees under the tent showing off their equipment, including a signal map of the entire subdivision (or maybe Roseville plus several nearby subdivisions?), going hundreds of miles from Sacramento to Donner Pass and also up the Sacramento Valley on different branches of the track. I watched as the bearded railroad worker scrolled around the schematic diagram, finding trains (including one 15,000 feet long), identified by head code and displaying each individual engine in the train and their position in the train; plus the state of each signal on the track network and each block of track, including several blocks that had been locked out because of track work.

Also under the signal tent I saw an older signal mechanism, equipped with an electrically-operated wheel that moved a colored filter in front of the white light bulb to change the signal between red, yellow, and green. (Most of what I know about railroad signaling comes from Thomas the Tank Engine, and the rest comes from reading Wikipedia; it was fascinating to see fragments of a real operational railway live and in person.)

There were other pieces of equipment on display, including a snow-cat that one could wait in line to climb up into (we skipped this), a pneumatic artillery gun that looked like it was used to fire avalanche charges into snow banks on Donner Pass, and a display of track repair including a crane that could operate on the tracks, and a saw set up to cut through track to remove and replace it. The whole impression was that this was set up by people who were excited to show off the things they work on; and because of that it was fun to see everything.

The forecast promised more rain, but the sky was just cloudy while we were checking out the train and the adjacent exhibits. More than once I felt a few drops of rain that seemed like it was the vanguard of more rain, but the rain did not follow up. We left the exhibits to eat lunch in old town Roseville, and while we were eating the sky opened up and the rain began to fall. (I saw on social media that the exhibition was closed early because of the threat of thunder. The storm had already disrupted the train's plans to traverse Donner Pass heading east; because of the forecast of snow the train would be rerouted to the north, thwarting the plans of every spotter planning on seeing it on its way through the Sierras.) We walked back to the train station in the pouring rain and huddled under the shelter at the train station until the westbound California Zephyr arrived well ahead of its timetabled arrival at 14:14. (The timetable is clearly padded to make up for the operational challenges of a 52-hour route across a freight network.) We boarded the last coach in the train and found our seats for the ride back to Emeryville.

The rain kept falling as we headed back to Sacramento and onward to Davis and into the Bay Area. As we crossed the rail bridge connecting Benicia and Martinez I realized that I could walk a few steps to the end of the train and look straight out onto the tracks receding behind us, offering a new and interesting view of the steel truss rail bridge flanked by two road bridges on either side carrying I-680 over Carquinez Strait.

We pulled into Emeryville and drove the rest of the way home in the driving rain. We had seen the world's largest steam engine, and had an adventure on the train to get there and back.