(Portland, OR) -- Amtrak is facing a lawsuit from half a dozen people injured in the deadly train derailment on a high-speed route from Seattle to Portland Monday. KOMO News reports the Chicago-based Clifford Law Offices is representing six victims who are planning to sue to pay for their injuries. The law firm says it's launching its own investigation into how the derailment happened. Three people were killed and dozens injured when the Amtrak 501 train derailed and spilled onto I-5 Monday.