(a) Except as provided in paragraphs (b) and (c) of this section, the position in a train of each loaded placarded car, transport vehicle, freight container, and bulk packaging must conform to the provisions of this section.
(b) A car placarded “RADIOACTIVE” must comply with train positioning requirements of paragraph (d) of this section and must be separated from a locomotive, occupied caboose, or carload of undeveloped film by at least one non-placarded car.
(c) A tank car containing the residue of a hazardous material must be separated from a locomotive or occupied caboose by at least one rail car other than a placarded tank car.
(d) Position of rail cars in a train. In the following table:
Position in Train of Placarded Cars Transporting Hazardous Materials
| RESTRICTIONS | Placard Group 1 | Placard Group 2 | Placard Group 3 | Placard Group 4 | ||
|---|---|---|---|---|---|---|
| Rail Car | Tank Car | Rail Car | Tank Car | Rail Car | Rail Car | |
| 1. When train length permits, placarded car may not be nearer than the sixth car from the engine or occupied caboose | X | X | X | |||
| 2. When train length does not permit, placarded car must be placed near the middle of the train, but not nearer than the second car from an engine or occupied caboose | X | X | X | |||
| 3. A placarded car may not be placed next to an open-top car when any of the lading in the open top car protrudes beyond the car ends, or if the lading shifted, would protrude beyond the car ends. | X | X | X | |||
| 4. A placarded car may not be placed next to a loaded flat car, except closed TOFC/COFC equipment, auto carriers, and other specially equipped cars with tie-down devices for securing vehicles. Permanent bulk head flat cars are considered the same as open-top cars | X | X | X | |||
| 5. A placarded car may not be placed next to any transport vehicle or freight container having an internal combustion engine or an open-flame device in operation. | X | X | X | |||
| 6. Placarded cars may not be placed next to each other based on the following: | ||||||
| Placard Group 1 | X | X | X | X | X | |
| Placard Group 2 | X | X | X | X | ||
| Placard Group 3 | X | X | X | X | ||
| Placard Group 4 | X | X | X | X | X | |
(1) Where an “X” appears at the intersection of a Placard Group column and a Restriction row, the corresponding restriction applies.
(2) “Rail Car” means a car other than a tank car.
(3) For purposes of this subpart, each unit of an articulated intermodal rail car shall be considered as one car.
[Amdt. 174-68, 55 FR 52680, Dec. 21, 1990, as amended at 57 FR 45464, Oct. 1, 1992; Amdt. 174-83, 61 FR 28678, June 5, 1996; Amdt.174-83, 61 FR 50255, Sept. 25, 1996; Amdt. 174-83, 61 FR 51339, Oct. 1, 1996; 64 FR 51919, Sept. 27, 1999; 66 FR 45383, Aug. 28, 2001]