Big Boy 4014 on trek from Marathon to Sanderson, Texas. – photo by Ken Grimm

The 4000-series Union Pacific steam locomotives were the largest built to operate on American tracks; indeed they hold the distinction of being the largest and most powerful such engines ever constructed for rail service in the world.

The 4-8-8-4 articulated locomotives are impressive in size and capacity. Entering service in 1941, the behemoths were a crucial element of the Second World War effort, moving critical, strategic material across the nation. A total of twenty-five Big Boys were built; today seven remain, on public display in cities across the United States.

Big Boy No. 4014 was delivered to Union Pacific in December 1941. The locomotive was retired in December 1961, having traveled 1,031,205 miles in its 20 years in service.  Union Pacific reacquired No. 4014 from the RailGiants Museum in Pomona, California, in 2013, and relocated it back to Cheyenne to begin a multi-year restoration process. It returned to service in May 2019 to celebrate the 150th Anniversary of the Transcontinental Railroad’s Completion.

Union Pacific web site (

Saturday morning, November 2, 1029, Big Boy No. 4014 chugged into Marathon, Texas, one stop in “The Great Race Across the Southwest,” celebrating the 150th anniversary of the Transcontinental Railroad’s completion.

An enthusiastic crowd waved the American flag, cheering and clapping as the 132-feet long, 1.2 million pound chugging leviathan blew its deafening steam whistle and came to a rest on the track that bisects the community. Rivers of steam from various ports created impromptu clouds temporarily obscuring workers and bystanders as the engine breathed in the clear, brisk morning air.

As workers serviced 4014, greasing drivers, wheels, rods, and inspecting the many external parts of the engine — the crowd entertained itself with many selfies and group pictures, getting up-close and personal with the beast. Several drones were observed in the sky taking advantage of a rare opportunity to document a piece of living history.

Some spectators tried to place pennies and other coins along the tracks to create flattened souvenirs, but the Union Pacific police stepped in, gently reminding the crowd “please do not place anything on the tracks. The tracks must be clear.”

Big Boy No. 4014 speeds over a crossing on its way to Sanderson, Texas. – photo by Ken Grimm

After getting the “all clear” from the service workers and railroad officials, the brass bell sounded signaling 4014’s readiness to get underway. As 300-lb-per-square inch pressurized steam entered the huge cylinders, the engine’s drivers forced the sixteen 68-inch driving wheels to slowly turn, gaining momentum as huge steam clouds belched into the crowd. The smoke box at the front of the engine spewed smoke and steam creating the familiar whoosh-whoosh-whoosh sound of a steam engine on the move.

Many people wanting to document the trek, capturing video and photos, played a game of leap-frog along Highway 90 where the train track ran — mostly — parallel to the road, deviating for a short distance as the tracks went south through a portion of the Del Norte mountain range.

Shutterbugs grabbed some photos, shot some video, as the rare sight passed — then jumped in their vehicles to race ahead and set up for for the next opportunity. The speed of the train seemed to be dependent on the curvature of the track and other factors, running an estimated 30-55 miles per hour on its way to Sanderson.

An enthusiastic welcoming crowd was waiting for 4014 as it entered the side track at the Sanderson Depot, where it would spend the night before continuing to Langtry the next morning.

Crews worked to secure the locomotive for the evening, setting up a security boundary to the punctuated loud releases of steam buildup from the boiler system. A cargo train approached the station on the main, active track from the east, affording visitors a rare opportunity to see live, active modern and historical power plants together as it passed the depot.

A diesel engine is part of the Big Boy train — a main function it provides is “dynamic braking.” Historically, to stop an older train mechanical friction hand brakes had to be applied to each car manually by brakemen, jumping from moving car to moving car, a dangerous and slow process. The brakeman’s job was one the most hazardous on the freight train. Many were thrown to their deaths underneath the wheels of the train.

George Westinghouse patented the automatic air brake system during the mid-19th century which eventually did away with this necessary task.

Today, friction brakes are still used, but activated by air pressure, controlled electronically or otherwise. Plus, in a modern train the engine itself can become a brake, translating the kinetic energy of forward motion into electrical current, dissipated as heat — “dynamic braking.”

Dynamic braking is the method of train braking whereby the kinetic energy of a moving train is used to generate electric current at the locomotive traction motors.

It works like this: While the train is coasting, the engineer, using an eight-notch controller similar to the throttle, energizes the traction-motor fields, causing the motors to act as generators. The resistance of the motor field acts as a brake on the locomotive, which in turn helps to slow the train. The electric current generated by the motors in the dynamic-braking mode is a waste product and is dissipated as heat in banks of resistors located in the locomotive carbody.

Dynamic braking is not a substitute for train air brakes (electronically controlled or otherwise), but a supplementary system that provides an additional means of train-speed control. website – Dynamic Braking

Big Boy No. 4014 is making several stops in Texas until November 12, 2019, when it crosses into Arkansas. It then journeys through Oklahoma, Kansas, Missouri, and Colorado before completing the journey back at its home base in Cheyenne, Wyoming, on November 27. Click the schedule link below for a list of destinations the locomotive will be visiting.

Big Boy No. 4014
Schedule of The Great Race Across the Southwest
Video: Last of the Giants—Union Pacific Railroad
Popular Mechanics: Why the Big Boy 4014 is Such a Badass Train
How a train uses Dynamic Braking
The Life of a Brakeman
Brakeman – American Rails

More Stories for you

• 2019 Fill the Boot donation drive is underway
SAN ANGELO, TX – The San Angelo Fire Department kicked off their “Fill the Boot” donation drive during an announcement…

• CVHP News: November 5, 2019
Join Senora Scott every weekday morning for CVHP News. This will be a webcast letting you know what we’re working on …

• Polling location at Belmore Baptist to Reopen
Update: Belmore Baptist Church, located at 1214 S. Bell St., has been cleared to reopen. SAN ANGELO, Texas – The …

• Concho Valley voters to decide ten state constitutional amendments, local ballot questions on election day
SAN ANGELO, Texas — On Tuesday, Concho Valley voters will decide ten state constitutional amendments, along with…

• Leadercast to inspire local women
SAN ANGELO, TX – Angelo State University’s Small Business Development Center has an upcoming learning opportunity for c…