Question: Alan Schilke is an engineer who made is mark on a steel roller coaster operating at Six Flags Magic Mountain which is located where?

Context paragraphs:
Full Throttle (roller coaster): Full Throttle is a steel launched roller coaster at the Six Flags Magic Mountain amusement park in Valencia, California.  The ride is designed by Premier Rides and featured the world's tallest vertical loop at 160 ft when it opened (this record is now held by Flash, a steel roller coaster at Lewa Adventure, China).  It is also the first roller coaster to feature a top-hat element on a loop.  It officially opened to the public on June 22, 2013.

Ninja (Six Flags St. Louis): Ninja is an Arrow Dynamics/Vekoma steel roller coaster located in the Studio Backlot section of Six Flags St. Louis in Eureka, Missouri.  The ride features a loop, a sidewinder, and a double corkscrew.  It was originally built for and located at Expo '86 in Vancouver, B.C., operating as Scream Machine from May to October 1986.  It began operating as Ninja at Six Flags St. Louis in 1989.  The coaster was started by Arrow Dynamics, but when Arrow fell into bankruptcy, it was sold to Vekoma, who finished it.  The ride is formerly shared a name with Blue Hawk at Six Flags Over Georgia until that coaster's retheming in 2016.  Another roller coaster with the same name exists at Six Flags Magic Mountain, but that ride is an Arrow Dynamics suspended swinging coaster.  The Ninja, like most modern roller coasters, requires a minimum of two employees to dispatch the train.  One operates the main panel, which controls the restraints, gates, and has a section for the mechanics.  The other operator stands at the remote enable.  Both operators have to do an all clear sweep and thumbs up, then press their buttons at the same time.

Viper (Six Flags Magic Mountain): Viper is a steel roller coaster made by Arrow Dynamics of the United States.  The roller coaster is located in the Baja Ridge area of Six Flags Magic Mountain in Valencia, California.  Viper is the last of the three 7-looper roller coasters built by Arrow Dynamics to remain operating.  The other two, Shockwave at Six Flags Great America and the Great American Scream Machine at Six Flags Great Adventure, were demolished in 2002 and 2010, respectively.  The roller coaster replaced a HUSS ride type named Condor.

Goliath (Six Flags Magic Mountain): Goliath is a steel roller coaster made by Giovanola of Switzerland.  The hypercoaster is located in the Screampunk District area of Six Flags Magic Mountain in Valencia, California and is promoted with a sub-tropical theme that is characterized by ruins of the ancient Mayan civilization.  The ride is nearly identical to Titan at Six Flags Over Texas.  Its differences from its Six Flags twin is that Goliath lacks the 540-degree upward helix on Titan prior to the mid-course brake run (Goliath simply banks left to the brake run instead) and Goliath is also slightly shorter than Titan.

Flashback (Six Flags Magic Mountain): Flashback was a steel roller coaster made by Intamin of Switzerland.  The coaster was located in the Six Flags Plaza area of Six Flags Magic Mountain in Valencia, California.

Twisted Colossus: Twisted Colossus (formerly Colossus) is a steel roller coaster at Six Flags Magic Mountain amusement park.  Originally designed and built by International Amusement Devices, the roller coaster opened as Colossus on June 29, 1978.  It was the tallest and fastest wooden roller coaster in the world and the first with two drops greater than 100 ft .  Colossus became well known after appearances in film and television, including the box-office hit "National Lampoon's Vacation".

X2 (roller coaster): X2 (formerly known as X) is a steel roller coaster operating at Six Flags Magic Mountain in Valencia, California.  It is the world's first 4th Dimension roller coaster and was the final roller coaster conceived and installed by ride manufacturer Arrow Dynamics.  The ride is unique in that the trains' seats pitch 360 degrees forwards and in reverse independent of the main chassis.  The coaster initially opened to the public on January 12, 2002; numerous malfunctions delayed it from debuting in 2001 as was originally anticipated.  On December 2, 2007, the ride closed for its transformation into X2.  It was completely repainted, received new third generation vehicles, and featured new special effects including a sound system and a pair of flame throwers.  The ride reopened on May 24, 2008, following the upgrades.

Tatsu: Tatsu is a steel flying roller coaster designed by Bolliger & Mabillard at the Six Flags Magic Mountain amusement park located in Valencia, California, United States.  Announced on November 17, 2005, the roller coaster opened to the public on May 13, 2006 as the park's seventeenth roller coaster.  Tatsu reaches a height of 170 ft and speeds up to 62 mph .  The ride's name means "Flying Beast" in Japanese.  The roller coaster is also the world's tallest and fastest flying coaster; is the only flying roller coaster to feature a zero-gravity roll; and has the world's highest pretzel loop.  It was the world's longest flying coaster until The Flying Dinosaur surpassed it.

The New Revolution (roller coaster): The New Revolution (formerly known as Revolution, Great American Revolution, and La Revolución) is a steel roller coaster located at Six Flags Magic Mountain in Valencia, California.  Manufactured by Anton Schwarzkopf and designed by Werner Stengel, the roller coaster opened to the public on May 8, 1976.  The New Revolution is the world's first modern roller coaster to feature a vertical loop and has been recognized for that accomplishment by American Coaster Enthusiasts (ACE), who awarded the roller coaster its Coaster Landmark status.

Alan Schilke: Alan Schilke is an engineer and roller coaster designer based in Hayden, Idaho, United States.  He first made his mark on the industry by designing the 4th Dimension roller coaster, X, while working with Arrow Dynamics.  Schilke now works as a Design Engineer at Ride Centerline LLC.

Supporting paragraphs: Alan Schilke X2 (roller coaster)
Answer: Valencia, California