- Jennifer: "This thing looks like it's from the Middle Ages."
- Marty: "No... the 1890s. Doc is in trouble, Jennifer. The whole timeline's in trouble."
- — Jennifer and Marty after finding the steam time car
The steam time car was Dr. Emmett Brown's third successful time machine, after the temporal field capacitor and the DeLorean time machine; and his second time machine that was capable of transporting living beings.
Doc had previously built another time machine prototype, the Jules Verne Train/Time Train, but when he tried to leave on June 12, 1893 for 1985, the train crashed before temporal displacement could occur.
After Marshal James Strickland and his son Roger Strickland helped Doc, his wife Clara, and their sons Jules and Verne out of the crashed train, Clara noticed a steam tricycle. Doc asked the man where he got the machine and inquired as to the top speed of the vehicle. The man stated that he had purchased and imported it from Léon Serpollet in France, and that he had managed to get it to go as fast as eighteen miles per hour.
Doc stated that it was a good start, and decided to try to make his own time machine from a Serpollet tricycle. He used the time circuits and the flux capacitor from the Jules Verne Train on the steam time car, which he had modified from components of the hoverboard that was left behind when Marty McFly left 1885 for 1985. The frictionless dynamo from the hoverboard was able to store multiples of the 1.21 jigowatts that were necessary for time travel.
However, the stresses of space-time and the temperature variation would wreak havoc on the cast-iron frame of the steam time car. In addition, the car provided no protection for the driver, so Doc had to wear a diving suit when he traveled through time in the time car in order to survive. Because of this, Doc doubted that it would be possible to make a return trip in the vehicle.
He devised an idea for a time parachute, in which a person would ascend in a balloon to a distance of half a mile, and then would be released from the balloon. The person would fall at a rate of 35 feet per second, and would reach 88 mph between four and five seconds. Since the time circuits, frictionless dynamo, and flux capacitor are connected to the parachute, the person would travel through time. The time traveler would then pull the ripcord of the parachute once they traveled through time, and arrive safely on the ground in that time period.
He left his family for the future in the steam time car on August 13, 1893, and had intended to arrive back seconds after he left. The time travel was a success, however due to the 19th century parts he had to use, there was a fluctuation in the space-time continuum. Doc ended up in 2035 instead of 2015, and didn't return home for days.
Doc's wife Clara then wrote Marty a letter letting him know that Doc was missing, and left it with the Western Union office with instructions for it be delivered to Marty McFly at Hill Valley High School in 1986.
Marty received the letter, and looked for Doc in a secret lab that he was able to find, with the help of his girlfriend Jennifer. Marty and Jennifer had no idea when and where Doc had gone, so Marty wrote Doc a note and left it in the secret lab. Doc found the note in 2035, while he was being pursued by officer Griff Tannen due to the biological scan of his age not matching that of the fake identity he set up in 2015. He had intended to travel back to 2015, to pick up the parts he needed, at a time that his fake identity would still be valid. However, Griff shot an electrical surge at Doc as he was about to head back in the steam time car. This surge was meant to disable his bio-mechanical implants, but since Doc didn't have any, he suffered amnesia due to the jolt.
He found the note that Marty left, and headed to the time and place that was written there, since that was his only clue as to what was happening. Doc arrived at the date on the note, March 3, 1986, in his secret lab. However, upon arriving there, he had no memory of who he was, and he was confused about the date and the location of which he had arrived. Neither did he recognize Marty and Jennifer.
Marty and Jennifer decided to help the amnesiac Doc find the vehicle that had transported him there, not knowing which time machine he had used. They went to the spot where Doc had crashed into a STOP sign , but the steam tricycle was gone. They discovered that the towing service, Lee Bros. Towing & Repair, had left a flyer on the sign (attached with what appeared to be a piece of chewing gum) with their company name for the owner.
They then traveled to the towing service, and discovered that a man who worked for the company, Jack, already had a buyer for the car. He stated that he would sell it to them instead for $300. Since they didn't have the money, they sneaked into the lot, and found the car still hooked up to the tow truck. Knowing that they didn't have any way to get the money, Marty decided to steal the car, tow truck and all. Douglas J. Needles arrived and threatened to smash the car, so Marty started the tow truck and sped away from Needles, who pursued him in his Ford F-150.
Marty managed to outrun Needles, who crashed into a delivery truck loaded with boxes of eggs. Jennifer and Doc, who had split up from Marty once Needles arrived, joined back up with Marty, and they headed to the Lone Pine Mall to inspect the steam time car. They discovered that Doc had arrived in 1986 from 2035. Since the steam time car wouldn't survive another trip through time, Marty grabbed a radiation suit and headed with Doc to September 16, 2035 to try to find out what had happened to Doc, and why he lost his memory.
- Back to the Future (IDW Publishing)
- Back to the Future: Untold Tales and Alternate Timelines
- Back to the Future: Continuum Conundrum