Although the details of the backstory vary from park to park, all follow the same general story arcs. Sometime in the late 1800s, gold was discovered on Big Thunder Mountain in the American Southwest. Overnight, a small mining town became a thriving mining town (the name of the town varies from ride to ride. In the original California ride, the town is known as Rainbow Ridge. In the Florida version, the town is known as Tumbleweed, and in Paris, the town is known as Thunder Mesa). Mining was prosperous, and an extensive line of mine trains was set up to transport the ore. Unknown to the settlers, the Mountain was a sacred spot to local Native Americans and was cursed.
Before long, the settlers' desecration of the mountain caused a great tragedy, which, depending on the park, is usually depicted to be an earthquake (in the Paris and California versions of the ride), a tsunami (in the Tokyo version of the ride), a flash flood (in the Florida version of the ride), which befell the mines and town, and the town was abandoned. Sometime later, the locomotives were found to be racing around the mountain on their own, without engineers or a crew. The Big Thunder Mountain Railroad was founded in the old mining camp to allow tourists to take rides on the possessed trains.
In keeping with the theme, the station buildings on all four versions of the ride are designed to look as though they are the abandoned offices of a mining company from the mid to late 19th century. The mountains themselves are themed to the red rock formations of the American Southwest. The rock work designs in the California version are based on the hoodoos of Bryce Canyon National Park in Utah. In the Florida, Tokyo, and Paris versions of the ride, the rockwork designs are based on the rising buttes that are located in Utah and Arizona's Monument Valley. Special care was taken by the Imagineers to make it appear that the rocks were there originally, and the track was built around the rocks, unlike a number of earlier mine rides, which were built the other way around (by sculpting the rocks around the tracks). The action of the ride takes place completely in the sagging, rotting tunnels of the mountain. In contrast to most steel roller coasters, where the thrills come from the perception of flying through open air, the thrills on Big Thunder Mountain Railroad are meant to come from the perceived instability of the mine and its threats of collapse. Sound effects of a typical locomotive operation are piped into the surrounding scenery to add realism to guests viewing the ride from observation platforms, including the steam whistle sounding, even though there is no whistle displayed on the locomotives.
Big Thunder Mountain Railroad was designed by ImagineerTony Baxter and ride design engineer Bill Watkins, as Disneyland and Walt Disney World were both beginning to bear the entire financial burden place on Disney. The concept came from Baxter's work on fellow Imagineer Marc Davis' concept for the Western River Expedition, a western-themed pavilion at the Magic Kingdom, designed to look like an enormous plateau and contain many rides, including a runaway mine train roller coaster. However, because the pavilion as a whole was deemed too expensive in light of the 1973 construction and opening of Pirates of the Caribbean, Baxter proposed severing the mine train and building it as a separate attraction.
The Big Thunder Mountain Railroad project was put on hold again in 1974 as resources and personnel were being diverted to work on constructing Space Mountain in Tomorrowland, but this delay may have ultimately produced a smoother ride as the use of computers in attraction design was just beginning when the project was resumed. Big Thunder Mountain Railroad was one of the first Disney rides to utilize computer-aided design. The attraction first opened at Disneyland in 1979, and the Magic Kingdom's larger version in Florida opened in 1980. Tokyo Disneyland's version opened in 1987 and Disneyland Paris opened with its version in 1992. The Paris version's layout and structure were mostly based on the Florida version of the ride, but with several significant differences.
The revised European ride takes the form of a large island in the center of the Rivers of the Far West, accessed from its riverside station by tunnels underneath the water. The attraction in Disneyland Paris is the only Big Thunder Mountain to have been an opening-day attraction at its park. Hong Kong Disneyland does not have a Big Thunder Mountain Railroad attraction (or a western-themed Frontierland, for that matter). However, Grizzly Gulch has a theme similar to Frontierland. The main attraction, Big Grizzly Mountain Runaway Mine Cars, carries a similar theme to Big Thunder Mountain Railroad.
The early 1970s: Big Thunder Mountain Railroad is conceived by Imagineer Tony Baxter for Walt Disney World, but it is put on hold due to the construction of Pirates of the Caribbean.
1974: The project is put on hold again due to the construction of Space Mountain.
1979: Construction begins on the ride at Disneyland.
September 2, 1979: Big Thunder Mountain Railroad officially opens at Disneyland.
November 15, 1980: Big Thunder Mountain Railroad officially opens at Walt Disney World's Magic Kingdom.
July 4, 1987: Big Thunder Mountain officially opens at Tokyo Disneyland.
April 12, 1992: Big Thunder Mountain officially opens at Disneyland Paris along with the park.
January 7, 2013: Big Thunder Mountain Railroad closes at Disneyland for refurbishment, to include an entire replacement of new track (similar to the Space Mountain refurbishment), new trains, new scenery, and new effects.
March 17, 2014: Big Thunder Mountain Railroad reopens at Disneyland.
November 2, 2015: Big Thunder Mountain closes at Disneyland Paris for a year-long refurbishment. Its reopening is scheduled for December 17, 2016.
August 8, 2016: Big Thunder Mountain Railroad closes at the Magic Kingdom for a 4-month refurbishment. Its reopening is scheduled for November 19, 2016.
December 6, 2020: Following Walt Disney World's reopening after being temporarily closed during the ongoing COVID-19 pandemic, Magic Kingdom announced that Big Thunder Mountain Railroad would be close temporarily at Magic Kingdom for the refurbishment. Its reopening is scheduled for 2021 in time for Walt Disney World's 50th Anniversary celebration.
Tributes to predecessor
At Disneyland, Big Thunder Mountain Railroad was built on the land the Mine Train Through Nature's Wonderland used to occupy. Several tributes to the former attraction are present in the Disneyland version. A scaled-down Western town sits adjacent to the queuing lines and tracks near the station. A Western saloon, hotel, assayer's office, and mercantile appear among the buildings. This is the village of Rainbow Ridge, which used to overlook the loading platform of the sedate Mine Train through Nature's Wonderland. Many of the animal animatronics throughout the attraction are animatronic animals from the previous attraction. Other allusions to the Mine Train through Nature's Wonderland include the Rainbow Caverns (glowing pools of water by the first lift hill) and precariously balanced rocks in the third lift hill tunnel. Also, the T-Rex skeleton that the train passes through during the climax used to be one of the many sights seen in the Living Desert.
The name of the ride itself, "Big Thunder", was originally the name of a large waterfall the old mine train passed on its tour. "Little Thunder" was located nearby.
At the Magic Kingdom and at Disneyland, the ride is known by its full name of "Big Thunder Mountain Railroad". The Tokyo and Paris versions would drop the word "Railroad" in favor of the name "Big Thunder Mountain". Tokyo Disneyland's Big Thunder, which is almost identical to the Magic Kingdom's, opened in 1987, five years after the park opened. At the Magic Kingdom and Disneyland, the name of the ride is sometimes shortened to "Big Thunder Mountain", "Thunder Mountain Railroad", or even just "Thunder Mountain".
While the design of the Walt Disney World version of this roller coaster was done first, Disneyland's version was the first one to open. The track layout was mirrored, placing the attraction to the right of Rivers of America, if viewed from the central hub. (In Walt Disney World, the attraction is located to the left of Rivers of America.) To better fit with the adjacent Fantasyland areas of the theme park, the original Walt Disney World design had to be replaced with something more appropriate for Disneyland. The Florida, Tokyo and Paris versions of the ride use sharp-edged mountains and the vibrant colors of Monument Valley, Arizona, while Disneyland's version was developed with more rounded features and muted colors resembling the Bryce Canyon hoodoos in Utah.
Upon entering the attraction, the queue winds through a narrow rock wall and passing by the tracks. The surrounding walls were originally created from 100 tons of gold ore from Rosamond.
Leaving the outdoor station, trains enter a bat-infested tunnel, make a right-hand turn, then a left-hand turn before climbing the first lift hill, which takes trains through a cavern full of stalactites. Leaving the lift hill, the train drops away to the right, then levels out and makes a left-hand turn. The track then crosses under the second lift hill drop before making a right-hand turn. The sounds of coyotes can be heard howling at the train as it dives into an underground cave. At the end of the tunnel, the train hits a trim brake, exits the tunnel, and climbs the second lift hill. At the top of the lift, an animatronic goat bleats at passing guests as the train drops away to the right, cross under the lift hill, and rises up into a downward spiraling clockwise helix. Leaving the helix, the train shoots through a small canyon, then drops down into a mining camp, where it hits another trim brake. The train then makes a left-hand turn, enters another tunnel, and climbs the third lift hill. As the train climbs the lift, the tunnel is dynamited, and artificial smoke is blasted in guests' faces as the train crests the lift and exits the tunnel. The train then drops to the right, towards the river, then makes a right-hand turn and passes through a short tunnel. After crossing over the drop, the trains make a left-hand turn as they pass through the ribcage of a T-rex skeleton, hit a trim brake, then make a right hand turn into the final brakes. The train then travels by the buildings of Rainbow Ridge as it returns to the station.
California's version of the ride is the only version of the ride to feature an outdoor station. All of the other versions feature an indoor station.
On January 7, 2013, the ride was closed for an extensive refurbishment that included a new track, trains, scenery, and new effects on the third lift hill. The attraction reopened on March 17, 2014. The new track was fabricated by Dynamic Structures, the company that had previously rehauled the coaster track in Space Mountain.
Magic Kingdom version
In 2013, the queue for the Magic Kingdom's version of the attraction underwent an overhaul that introduced more extensive themed elements as well as interactive activities. The Big Thunder Mining Company is still very active here, under the management of Barnabas T. Bullion, with land grants and other documents showing a Sept. 23, 1848 date for the beginning of Bullion's operations at Big Thunder Mountain. As time passed into the 1880s and the supernatural incidents have started becoming more common, a letter from the Society of Explorers and Adventurers colleague Jason Chandler has served as an unheeded warning from Madame Zarkov of the Museum of the Weird to abandon mining operations at Big Thunder and try elsewhere. Other correspondences found within the offices include documents showing the BTMC's foreman George Willikers has been taking more than his fair share from the workers, as well as warnings from the Sheriff about the bumbling criminals Theodore and Amos from The Apple Dumpling Gang making trouble the next town over.
Interactive elements within this new queue include a number of inventions guests can interact with such as a Subterrascope that allows one to view the workers in the mine in the Foreman's office, an Auto-Canary machine in the Ventilation Control room that allows people on the surface to monitor the air condition deep below, and many opportunities for guests to detonate TNT blasts on the mountain itself in the Explosives room and other areas overlooking the mountainscape.
For the most part, the track layout of the Magic Kingdom's version is a mirror image of the Disneyland version.
Riders board the trains in an enclosed loading station on a hillside. Leaving the station, trains make a left hand turn into a bat-infested tunnel, make a slight right turn, and climb the first lift hill. At the top of the lift hill, trains pass under a waterfall and drop to the left. This is followed by a right-hand turn, after which the track crosses under the second lift hill and drop. After crossing under the second lift hill drop, the track goes through a 270-degree clockwise spiral and passes through a short tunnel. Trains emerge from the tunnel and pass through the flooded town of Tumbleweed. The train passes over a decaying trestle (where the track is slightly banked from side to side), before entering Dave V. Jones' Mine, where it hits a trim brake. Trains then make a left-hand turn and climb the second lift hill.
At the top of the second lift hill, trains drop to the left and cross under the lift hill, before rising into a 540 degree downhill counterclockwise helix, passing over a broken trestle. Leaving the helix, trains shoot up across a small hill, make a slight right turn, then drop through another tunnel and hit a trim brake. The trains then make a right hand turn into a tunnel and climb the third lift hill. As the train climbs the lift, an earthquake hits and makes the train cars sway from side to side (the effect achieved by slightly banking the track). Leaving the lift, trains emerge from the tunnel, crest a small rise, and drop to the left towards the Rivers of America. After traveling along a short section of straight track, the ride then makes a left-hand turn through a short tunnel and crosses a short bridge. The train then makes a right-hand turn, and passes through the ribcage of a T-Rex skeleton as it hits the final trim brake, makes a left hand turn past some geysers and hot springs, and rises into the final brakes. The train then coasts back to the station.
The Florida version was allocated more space in the park, and so the Monument Valley-inspired ride structure assumes 2.5 acres, 25 percent larger than the Disneyland version.
The Florida version was closed for refurbishment from August to November 18, 2016.
Big Thunder Mountain at Tokyo Disneyland is similar to the Florida ride, but there are some differences in the ride layout. After going under the second lift drop, the Florida version does a 270 degree clockwise drop, then passes through the town of Tumbleweed, a short mine, and makes a left turn onto the second lift hill. On the Tokyo version, the track goes around a turn to the left and dives into an underground cave, mirroring the California version of the ride. More significantly, the final segment of the ride is different. Instead of crossing back over the drop from the third lift hill, the track makes a 180 degree turn to the right before dropping out of a tunnel, through the Boneyard/geyser scene, into a short tunnel. The track then makes a right hand turn into the final brakes. The trains pass in front of the station building and then turn back into the loading area.
In January 2020, a Single Rider queue was added to Tokyo Disneyland's version. 
Disneyland Paris version
While primarily based on the Florida version, Paris's version is unique in that it is situated on an island in the middle of the Rivers of the Far West, where Tom Sawyer's Island would normally sit. It is also the only version of the ride to be an opening day attraction. The Paris version underwent a 13-month refurbishment from November 2015 to December 2016; updates included the replacement of track and scenery, plus the installation of mapping effects on the third lift hill (similar to the California version) and the installation of interactive games in the queue line.
Guests board the trains at a station on the mainland. Immediately upon leaving the station, trains dive into a tunnel that transports them under the Rivers of the Far West to the island where the ride is located. The train makes a right-hand turn and makes a quick steep rise before starting up the first lift hill. As trains climb out of the darkness of the underwater tunnel, stalactites and stalagmites can be seen growing next to the track. The sounds of bats swooping up above can also be heard. At the top, a waterfall parting around the tracks suggests that the tunnel is flooding. Trains pop out of the tunnel, leave the lift hill, and drop around a left-hand turn, pass through a small cave, then make a swooping right turn. If the trains are being dispatched timely, when the train goes through this curve, it will appear to make a near-miss with a train in the 540-degree helix.
After this turn, the trains pass under the second lift hill and its drop, making a slight hop, before making a left hand turn onto a trestle. The train runs along the Rivers of the Far West, across the water from Phantom Manor, then makes a slight right-hand turn and suddenly falls through a washed-out section of the trestle. The trestle drop also contains an on-ride camera. After dropping down to the water level (with water jets on the sides of the track simulating a splashdown), the trains go around a left turn on an unstable portion of trestle enter a mining camp, and begin to climb the second lift hill.
As trains start up the lift hill, two tied down donkeys can be seen to the right side of the track, braying at passing trains, with an empty watering pail in front of them. A goat can be seen pulling on a work shirt hanging on a clothesline to the left, as the trains pass a parked steamroller and the mine elevator, and travel under a water tower.
At the top of the lift, The Twilight Zone Tower of Terror in the neighbouring Walt Disney Studios Park can be seen on the horizon before the trains drop around a left turn and cross back under the lift hill. The prerecorded sound of screeching wheel flanges can be heard as trains go around the curve. As the train comes out of the drop and goes over another rise, it passes a sign warning of a broken trestle that is mounted to the water tower post (this warning sign can also be seen by sitting in the very last row of the train and looking backward while going up the lift hill). Cresting the hill, trains cross over the broken trestle and spiral down through a 540-degree counter-clockwise helix.
Exiting the helix, the trains pass through a short cave and go over a quick airtime hill as they shoot down a canyon. As the trains drop through the tunnel and pass over a trim brake, a loud gust of wind is heard. Trains then make a right-hand turn on another trestle that seems to creak under the weight of the train as they enter a tunnel with signs warning of blasting over the portal and climb the third lift hill.
As the train starts up the hill, the tunnel is dynamited, and artificial smoke is blasted in guests' faces as the train crests the lift and exits the tunnel (like California, the third lift hill was originally a simulated earthquake prior to refurbishment). The train crests a small hill, then drops to the left onto a straightaway alongside the river, speeding up as it enters the return tunnel. The train encounters a swarm of bats in the tunnel as it makes another sharp counter-clockwise turnaround and goes down a steep drop to cross under the water. The trains continue to accelerate through the dark until it pops out of the exit portal on the mainland. The train then coasts past the station, through the loading dock, and then turns around to reenter the station.