Cal. Code Regs. tit. 8, § 7038 – Transportation of Employees.

(a) Except as provided in subsection (b) of this section, transportation of employees over mine railroads when going on or coming off shift shall be in man cars especially designed for such transportation.
(b) Where not more than five men are going on or coming off shift, they may be transported in mine cars.
(c) All man cars and mine cars carrying men going on or coming off shift shall be secured with safety chains to prevent such cars from running away should a coupling fail.
(d) Every mine car used for transportation of employees shall be provided with a positive locking device that will prevent accidental dumping of the car.
(e) A train transporting workers shall be pulled, not pushed, by the locomotive, and shall be operated at a safe speed.
(f) (9-67) Every man car or mine car, truck, or other vehicle used for transportation of employees shall be provided with safe and secure seats, and shall be protected on sides and ends to prevent falls from the vehicle.
Means shall be provided whereby employees can safely mount or dismount the vehicle.
(g) (9-113) Vehicles transporting workers shall be operated cautiously and with due regard for the safety of employees. Such vehicles shall be operated at a safe speed.
(h) (9-114) Employees shall not be required or permitted to get on or off a moving vehicle.
(i) (9-99) Supplies, materials, and tools other than small hand tools shall not be transported with men in man trip cars or vehicles. Man trips shall be operated independently of ore and supply trips.
(j) (9-116) During shift changes, the movement of rock or material trains shall be limited to areas where such trains could not present a hazard to men coming on or going off shift.
(k) (9-117) Men shall not ride between cars or on top of loaded cars.