It doesn't take long for combat to start. As soon as the posse sees the carnage outside, they spring to action, with Bill and Hardtack giving out the orders. Bill shouts out for Adelita, Deputy Jimenez, and Sanchez to get up on the roof and take cover behind its crest. Meanwhile, Sheriff Weller, along with Cassidy and Reed from the casino, take their positions in the train station's windows and Bill does the same, trenching himself under it with his hawken rifle in hand.
Hardtack turns over a round table that was there for train passengers to wait and maybe play cards as they do so and holds it between his arms, beckoning Isaac to get behind it, and together they set up at the outside door, ready to burst out.
Perhaps that's when it all had gone wrong already. The Marauders, despite their craziness, have an advantage of organization, and their leader instantly takes the first step. A lit dynamite lands in front of the door, and it pushes the pair backwards, taking out chunks of their makeshift shield in the process. Shots are exchanged as Isaac and Hardtack make their way out and immediately find more solid cover.
The roof squad, lead by Adelita, take pot shots into the train carts' windows, managing to singe and graze some of the wild Marauders, who laugh like crazy at their blood being spilled, as if it weren't gunshot wounds, but feathers tickling them in their sensitive spots.
Bill locks himself on the sole Marauder outside of the train, who's already got speed running towards the station, a half-naked, well-tanned and muscular man running towards the building with a bowie knife in each hand. The crazed Marauder leaps through a blown-out window and swipes at Bill, but the Mountain man's cougar-like instincts allow him to dodge.
On the roof, Adelita is switching targets like it's a shooting range. Shoot, cock back, a satisfying click from the mechanism, a spent casing rolling down the roof shingles, another shot rings out. She tries her best to take advantage of the elevated position, and along with the men accompanying her up top, they inflict some serious damage on the crew that has so far been moving south-to-north completely unopposed, murdering folks, robbing cities and burning down churches and ranches as they went. How they went about acquiring a train and modifying it to a murder fortress is a mystery to any one of them, but Adelita makes it clear that she wants to draw blood, and she manages to.
Hardtack and Isaac pull a smart trick off as they move their table-shield to one side, prop it up against a boulder and leave Isaac's funny hack on top, making it seem like they're still hiding behind it. While their trickery is uncovered by a single Marauder, the Wild man rushes into the train car he's shooting from and viciously thrusts the sabre through the gangster's throat, silencing and killing him at the same time - the gurgles of the marauder choking on his own blood are not enough to warn his mates.
The gunfight rages on, and the entirety of Santa Fe is probably cowering behind their windowsills, guns or improvised weapons in hand, as they hear the pinging of bullets in the distance, but they all get a big old scare when the whole town shakes from an explosion. It's the Marauders' leader-apparent - Virgil "Skull" Turner, a freakish looking man with a skull-like painting or tattoo over his face, and a trenchcoat adorned with several bloodied sheriff stars - seemingly taken from the bodies of murdered adversaries - dynamite that lands on top of the train station's roof, halfway into burning down.
Adelita and the Sheriff's Mexican deputy, Sancho Jimenez, look sideways at the hissing dynamite, then at each other - and both of them try to roll away from it, but it's much too late and they are much too slow. The gunpowder-filled stick explodes in a raging inferno of fire and debris as the roof shingles mix themselves with the pressure and blow both Deputy Jimenez and Adelita apart. A sudden hole in the ceiling, and body parts flown about, the pair are dead instantly, and with no ceremony. There's no heroic moment, neither one of them jump on the dynamite to save the other - it's just pure Wild West, a well-thrown explosive landing exactly where it isn't supposed to be, and then tearing two bodies apart, extremity by extremity.
The explosion is used as cover for one of the Marauders to enter into close-quarter combat inside the train station, but Sheriff Weller is ready for him, and unloads his two revolvers straight into the man's chest with enough force that the raider falls backwards out through the blown door, and lands in the grass, bleeding out. "Skull" sees this, along with a few of his other men, and turns to the gangster-conductor - "Start fuckin' rollin' the train, ya useless bastards!!!" he yells, and immediately, the train does start moving. Whoever or whatever they are, despite their apparent craziness, they are well-organized and perhaps they leave a few of their men and women behind, but they are able to cut their losses and leave.
While that's happening, Bill is engaged in a stylish fight with the Marauders' berserker, the crazed, shirtless man swinging two bowie knives at him while Bill just calmly dodges out of the way and even manages to reload his hawken rifle while engaging the brute. Perhaps he's on drugs?
One way or another, it's the Skull's parting dynamite throw that lends to two of the casino's security workers, Cassidy and Reed, that even more brutally tears them apart into pieces and leaves yet another smithering hole in the train station. Sheriff Weller is injured proper as well, having taken a few gunshots, but he shows extreme resilience and keeps fighting, even runs out the door to pursue the retreating berserker, whom he knocks out with the butt of his revolver to arrest him later. At that time, the train is already halfway gone, and Bill seeks the opportunity to shift positions, running out back and climbing the ladder to the train station's roof.
Meanwhile, Hardtack and Isaac are busy fighting off the two last Marauders who have stayed behind, when inspired by the Sheriff's actions, Hardtack takes his finishing blow with the sabre's guard, using it as a boxer to knock out the last man endangering them before the train finally pulls off completely.
It's only a few seconds later that Bill Williamson makes it up the roof, having shifted directions, and climbed up the ladder faster than a mountain lion makes it up a rocky hill. He skulks around the blown-apart bodies of Adelita and Jimenez, and charges directly at Sanchez, gripping his hawken rifle by the barrel, and smacks him across the back like he's playing baseball. The Mexican bodyguard yelps and falls forward, crashing down from the roof right next to Isaac, who actively places the outlet of his shotgun right in front of Sanchez's face.
The Marauder Train now gone, and Sheriff Weller too busy treating his own wounds as well as arresting the two marauders who were left behind, the posse - though now missing an Adelita - easily manages to sneak in a capture, and they leave the bloody, burned, tainted battlegrounds behind, Sanchez in a rope tie. They find a nearby shack just off the train track and tie Sanchez down in there, still unconscious - but they gag him nevertheless. Bill, Isaac and Hardtack then quickly return to Santa Fe center, aiming to pick up their horses in order to take them outside of town to interrogate their captive...