49 CFR §215.305
- (a)Maintenance-of-way equipment (including self-propelled maintenance-of-way equipment) described in § 215.3(c)(3) shall be stenciled, or marked—
- (1)In clearly legible letters; and
- (2)In accordance with paragraph (b) of this section.
- (b)The letters “MW” must be—
- (1)At least 2 inches high; and
- (2)Placed on each side of the car.