LEGO Dark Stone Gray Train Chassis 6 x 24 x 0.7 with 3 Round Holes at Each End (6584)

LEGO Dark Stone Gray Train Chassis 6 x 24 x 0.7 with 3 Round Holes at Each End has been used in at least 2 LEGO sets over the past 21 years, since it was first used in 2003. You can also find this part in at least 6 other colors. It has a design ID of 6584 which can usually be found molded into the bottom of the part.