LEGO Medium Stone Gray Train Base 6 x 34 Split-Level without Bottom Tubes (87058)

LEGO Medium Stone Gray Train Base 6 x 34 Split-Level without Bottom Tubes has been used in at least 4 LEGO sets over the past 13 years, since it was first used in 2011. You can also find this part in at least 4 other colors. It has a design ID of 87058 which can usually be found molded into the bottom of the part.