A toy vehicle adapted for running on rails and a toy construction system

A toy vehicle configured for running on rails, the toy vehicle comprises a chassis comprising a first end and a second end, two side faces extending in the longitudinal direction of the toy vehicle and a top portion, the toy vehicle comprising at least two axles, said at least two axles comprising a wheel, and where the chassis comprises oblong recesses positioned on the inner surface of the chassis, the oblong recesses adapted to obtain a protrusion of a wheel or an end portion of the at least two axles, the chassis comprising two or more axle support arms adapted to support the at least two axles, characterized in, that the two or more axle support arms are adapted to provide a void allowing movement of the two or more axles within that void of the axle support arms, so that the wheels are slidable within the oblong recesses but to avoid disengagement between an oblong recess and the protrusion of a wheel or an end portion of the at least two axles, respectively, and so that the axle support arms only add friction to the axles when it is necessary to keep the wheels in place and to avoid detachment.