The Sacred Engine

The Sacred Engine was the the locomotive of Snowpiercer, pulling 59 cars with ease at 80 km/h. It uses a perpetual motion engine as it's propulsion method to power it and the train through it's endless journey. 
It's (presumably) perma-coupled to the next car, the Machinery Car (like a steam locomotive tender), to help it run properly. 
== History ==
The engine was built in 2013 by Mr. Wilford when he realized CW-7 would freeze the world.
Since departure, the engine plowed through snow and broke ice without issue, despite all the turbulence caused by the impacts.
== Through-out the Movie ==
The locomotive ran without issue or any signs of slow-down until 18 years later, parts became extinct. Because of this, Wilford started bringing kids under 5 from the tail to stuff them into the engine and help it run manually. 
In the Great Curtis Revolution, Curtis shoved his arm in-between gears beneath the interior paneling to save Tim, which caused a critical engine shutdown. Because of this, the engine deployed the manual input cockpit and brain-washed Andy got into the cockpit before it retracted again, to manually re-start the engine (presumably). 
The engine was presumably damaged after the explosion of the kronole bomb in the Machinery Car and was derailed & destroyed further in the avalanche the explosion caused. Yona and Tim, the only 2 survivors, get out of the engine after it derailed to find life outside.
== Technology ==
The locomotive is autonomous and powered by a perpetual motion engine, requiring it's "tender", the Machinery Car, to properly run. There are headlights on the front of the train, the main one having a bullbar, despite the fact that there is no windows to the outside. 
There are intakes which collect snow from the outside and sends them to the Water Supply Section, where the snow is turned into water and the water is treated to be safe to drink, before it is supplied throughout the entire train. 
Inside, there is a Wilford Industries logo on the wall that is secretly a telephone. Mr. Wilford used this to communicate with Gilliam in secret, and later with Egghead in the movie.
== Interior ==
Most of the walls are bare with what seems to be open shutters covering them. At the back there is a big vault-like metal door that can be opened by a lever, and the flooring is what seems to be uncovered steel. There are also gray metal cabinets that can be presumed is for storage.
Towards the middle however, the floor is elevated (for machinery space) and luxuriously tiled and the pattern has a Wilford Industries logo. There are wooden cabinets which all seem to serve a different purpose, with one of them being a grill to cook meals, another being used to store spices. 
Towards the front, it returns to a more industrial style, with cat-walks leading up to the core, or the heart of the engine. When needed, the core will automatically open up and deploy a "manual input cockpit," which then a driver can get inside and do what is required to get the engine running properly again.
== Exterior ==
The exterior of the sacred engine is rather interesting. It seems to be inspired off of 1930s stream-lined steam locomotives, however it has a plow/"ice-breaker" at the front. The roof of the engine has a hump, and 2 "wings" hang over the side of the locomotive from that hump as it comes back down. The engine bears a silver-ish gray color, and the inner metal in-between the outer shell and the interior is dark red, like organs and muscles. There are multiple headlights despite the lack of any windows, with one at the very nose.
== Trivia ==
* Mr. Wilford built the engine when he realized CW-7 would freeze the world.
* Despite Curtis shoving his arm into the machinery and causing a critical engine shutdown, the locomotive didn't stop or slow down. We can assume it continued running by momentum and left-over energy, however it is unconfirmed.
* Some users speculate there are "turbines" in the "wings" that stick out of the top, however this is unknown.
* It could be theorized that the main headlight at the front is the only window that can be looked out through in the manual input cockpit, however this is unlikely.
* The exterior seems to be inspired by 1930s art deco streamlined locomotives, specifically a stream-lined New York Central Hudson.
* The locomotive has a 0-4-4-0 wheel arrangement. 
* In some concept art, the locomotive was supposed to have a deployable plow at the front, which would deploy when the train needed to break through ice.
* When Claude shoots up towards the ceiling, Mr. Wilford gets worried and tells her to mind the engine. Because of this, we can speculate that after 18 years the engine has began suffering mechanical issues besides parts going extinct, and that Wilford is referring to the engine instead of Claude when he says that she is getting sensitive. 
* It is implied the "core" of the perpetual motion engine doesn't need to be running at all times to keep the locomotive going. We only see it active when Wilford walks Curtis up to it.
* It's implied Mr. Wilford never leaves the engine, which means he would have to sleep in it. However, there are no beds present in the interior. It could be that one of the wooden cabinets open up to a bed, however that would require more external space.
== Gallery ==
Movie
File:Filmtrainfront.png|Front
File:Filmtrain yekaterinaoverhead.png|Overhead View
File:FilmTrainOverhead.png
File:Filmengine avalanche.png
File:Filmengine tunnel.png|Coming out of a tunnel derailing
File:Filmengine derailed.png|Derailed
File:Filmtrainrear.png|Rear View
File:FilmTrainSideView.png|Side View
Artwork/Promotional
File:FilmTrainWheels.jpg|Artwork of the wheels
File:FilmTrainMain.jpg
File:FilmTrainFront.png|Promo Image
File:FilmTrainTop.png|Poster
Concept Art
File:Filmengine interiorset.png
File:FilmTrainConceptArt.png
File:FilmTrainConcept1.png
File:FilmTrainConcept3.png
File:FilmTrainConcept4.png
File:Filmtrainconcept.png
File:Filmtrainconcept2.png
File:Filmtrainconcept3.png
File:Filmtrainconcept5.png
File:Filmtrainconcept6.png
File:Filmtrainconcept7.png
File:Filmtrainconcept8.png
File:Filmtrainconcept9.png
File:Filmtrainconcept10.png