S.W.A.T.

Jim Street (Colin Farrell), a former U.S. Navy SEAL and hot-shot cop from the Los Angeles Police Department and his SWAT team are sent to stop a gang of robbers who have taken over a bank. His high-tempered partner and close friend Brian Gamble (Jeremy Renner) disobeys an order to hold their position and engages the bank robbers, accidentally wounding a hostage in the process. Gamble and Street are demoted by Captain Fuller (Larry Poindexter), the commander of the LAPD Metropolitan Division. Gamble quits following an intense argument with Fuller, and Street is taken off the team and sent to work in the "gun cage", where he looks after the gear and weaponry. Six months after the incident, the chief of police calls on Sergeant Daniel "Hondo" Harrelson (Samuel L. Jackson) to help re-organize the SWAT platoon. Hondo puts together a diverse team, including himself, Street, Christina SÃ¡nchez (Michelle Rodriguez), Deacon Kaye (LL Cool J), TJ McCabe (Josh Charles), and Michael Boxer (Brian Van Holt). The team members train together, eventually forging bonds of friendship. As a result, their first mission to subdue an unstable gunman is a success.
Meanwhile, French drug lord Alexander "Alex" Montel (Olivier Martinez) arrives in Los Angeles and goes to a local restaurant to kill his uncle for holding back the family money from him. While driving to the airport, uniformed LAPD officers stop Montel for a broken tail light and later detain him to get a full positive I.D. on him; they learn through Interpol that he is an international fugitive wanted in over a dozen countries. But as Montel is being transferred to prison, his associates, dressed as LAPD officers, attempt to rescue him as he rides the Los Angeles County Sheriff's Department bus. Hondo's team arrives in time to kill the two gunmen and recapture Montel. As Montel, under SWAT escort, approaches the police station, reporters crowd around them, prompting Montel to yell to the cameras that he would "give 100 million dollars to whoever gets him out of here". The LAPD makes plans to transfer Montel into federal custody. They initially plan for travel by air, but a mysterious attacker shoots down the helicopter with a high-powered rifle. The police next send out a large convoy, which gang members attack and discover to be a decoy, at the same time as Hondo's team is spiriting Montel away in two SUVs. However, while driving Montel into federal custody, TJ had been plotting with Gamble, and the two succeed in taking Montel from the other officers, critically wounding Boxer in the process.
Hondo and the rest of his team give chase for a final battle against Gamble's group. Fuller later informs them that Gamble intends to fly Montel out of the United States. Fuller dispatches every officer to an airport to prevent the escape. As Hondo and his SWAT team race across town, they observe a plane flying at lower than normal altitudes and deduce correctly that the plane is the one expected by Gamble. They decide to go after the plane, as available units are at the airport and won't make it in time. Before Gamble's group can take off, the team intercepts it, and a gun battle ensues, killing Gamble's remaining thugs, although wounding SÃ¡nchez. TJ commits suicide out of remorse for his betrayal of the team and to avoid being captured. Street pursues and inadvertently kills Gamble by knocking him under the wheels of a passing train, decapitating him. Fuller and the rest of the LAPD arrive to take care of everything else. Fuller thanks Hondo and his team for their success but tells them the job wasn't finished as Montel was not yet in federal custody. Hondo and his team deliver Montel to a federal prison to await trial. On the way home to Los Angeles, a report of a holdup in progress comes over the police radio and despite the team being two officers down and off shift for the past twelve hours, Hondo, Street, Kaye, and Sanchez decide to help anyway.

Question: Who is decapitated by a train?
Answer: Gamble