§ 13.61. Tank cars.

 (a)  The track of tank car sidings shall be approximately level and the wheels of cars shall be blocked at both ends while loading or unloading liquefied petroleum gas.

 (b)  A sign shall be installed at the active end or ends of the siding while the tank car is connected for loading or unloading. Such sign shall be of such standard size and form as used in the industry.

 (c)  An authorized attendant shall be present at all times while tank cars and trucks are being loaded or unloaded.