Engine Gattai Kyoretsu-O

"Engine Fusion! Kyouretsu-O, Tune up! Go-on!"

Engine Gattai Kyouretsu-O (炎神合体キョウレツオー), known as the "Powerful King of Trains" (強大な列車の王, Kyodai na Ressha no O), is formed when Engine Kishamoth, Engine T-line and Engine K-line combine together. Kishamoth serves as the main torso, T-line serves as the right leg, and K-line serves as the left leg.

Sosuke Esumi is able to get the 3 Ancient Engines to unite into Kyouretsu-O. Go-onRed pilots the mecha from the cockpit, as he is able to understand the Ancient Engines for some reason, allowing the robot to engage in a dynamic fight using its true power.

Kyouretsu-O is extremely powerful, and he also has the ability to shoot out a gust of cold air from Kishamoth's nose, which is at a temperature so cold, it can freeze magma. Attacks include "Railway Chop" (電車道チョップ, Denshamichi Choppu), "Dinosaur Kick" (ダイナソーキック, Dainaso Kikku), "Kyouretsu Dino Bite" (キョウレツダイナバイト, Kyoretsu Daina Baito), and "KishamoSteam" (キシャモスチーム,Kishamosuchimu).

Kyouretsu-O's finishing move is the "Kyouretsu Express" (キョウレツエクスプレス, Kyōretsu Ekusupuresu), where it first uses the KishamoSteam, then slams a white-hot Railway Chop through even the toughest of Banki.

Engine-O G12
See also: RPM Ultrazord

"G-12 formation - Engine Fusion! Engine-O G12, tune up! Go On!"

Engine-O G12 (エンジンオーＧ12, Enjin'ō Jī Tuerubu), also known as the "Ultimate King Who Triumphs Over Evil" (全ての悪を制する究極の王, Subete no Aku o Seisuru Kyukyoku no O), is a combination of Engines 1 to 12, piloted by the five Go-Ongers and the Go-On Wings team. The combination is simple; Engine Gattai Kyouretsu-O's chest parts attach to Engine-O G9's. The tusks of Kishamoth adhere to the back of G9's head, creating a bigger helmet-piece. Kyouretsu-O's body splits in 2, attaching as leg pieces between the Engine-O legs and Carrigator's feet parts. Birca and Gunpherd are then stored inside those two pieces, allowing the other two trains to attach in their place as the new formations arms. Buson gains face armor.

Its techniques are G12 Punch (Ｇ12パンチ, Ji Tuerubu Panchi) and G12 Kick (Ｇ12キック, Ji Tuerubu Kikku) and its finishing attack is the G12 Grand Prix (Ｇ12グランプリ, Ji Tuerubu Guran Puri), generating aura versions of Engine-O, GunBir-O, SeiKuu-O and Kyouretsu-O to attack the enemy before charging while generating a incinerating aura. With Go-Roader GT, it can execute the Go-Roader Strike (ゴローダーストライク, Gorōdā Sutoraiku).

A more advanced finisher technique which is G12's ultimate techique was used in the finale against Crime Minister Yogoshimacritein to defeat him is the G12 Final Grand Prix (Ｇ12ファイナルグランプリ, Jī Tuerubu Fainaru Guran Puri), involves G12 transforming itself in a fiery aura resembling a phoenix that rammed right through Yogoshimacritein's body, allowing the Go-onger team to scrap him once and for all.

G12 stands at a remarkable 93 meters (305 ft. and 1 in.) tall, making it the largest Engine combination made.

Go-Onger vs. Gekiranger
During the events of the vs. film, the Go-Ongers and the Gekirangers in SaiDai GekiRinTohja unleashed a powerful combination attack called the Engine Beast Grand Prix (炎神ビーストグランプリ, Enjin Bīsuto Guran Puri), where all of the used GekiBeasts, RinBeasts, and Engines were fired to reseal Long.

Samurai Formation 23
The Samurai Formation 23 (サムライフォーメーション23, Samurai Fōmēshon Tuentisurī) is a formation between SamuraiHaOh and Engine-O G12 in Samurai Sentai Shinkenger vs. Go-onger: Ginmaku Bang!!. In this form, ShinkenOh, DaiKaiOh, MouGyuuDaiOh, Kyouretsu-O, and Engine-O G9 use the Ika Tenku Buster to execute the Samurai Engine Super Grand Release (侍・炎神・スーパー大開砲, Samurai Enjin Sūpā Daikaihō) attack.