49 CFR § 215.305
Stenciling of maintenance-of-way equipment
November 18, 2020
(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.
[44 FR 77340, Dec. 31, 1979, as amended at 45 FR 26711, Apr. 21, 1980]