Technical Alignment Note: UIC Loading Guidelines (Volume 2, Goods, Version 01/04/2026, 10th edition) – Loading Method 9.2 Container Marking Examples and ISO 6346:2022

The page 1-4 wording introduces examples as “Markings indicating their height or their height and width (in accordance with ISO6346), e.g.:” [U1]. The example row then combines two different marking systems: ISO-style height marks and UIC Class 2 / Class 3 height-width pictograms.

For ISO 6346:2022 height marks, Annex F uses a metric height with the unit m and an imperial height in feet and inches, for example 2,9 m / 9′ 6″ for a 9 ft 6 in high container [I1]. The UIC Class 2 / Class 3 pictograms, by contrast, use an upper group for height in metres and a lower group for width in metres, without the abbreviation m [M1].

The sentence “These markings are mandatory for Ct’s with a height greater than 8 ½ feet” should also be scoped, because it follows the mixed example row [U1]. Under ISO 6346:2022, the mandatory height-mark trigger is containers higher than 2,6 m / 8 ft 6 in [I1]. The UIC Class 2 / Class 3 pictograms are governed separately by Table 1 and UIC Code 592 [U2] [M1].

Separate or caption the examples by marking system. Suggested wording:

“Containers may bear dimensional markings under different marking systems. ISO 6346 height marks and UIC Table 1 / UIC Code 592 Class 2 and Class 3 height-width pictograms should be read separately, for example:”

• ISO 6346:2022 height mark, where required: 2,9 m / 9′ 6″
• UIC Class 2 / Class 3 height-width pictograms, where applicable: 2,6 / 2,5 and 2,6 / 2,6

Suggested scoped mandatory-marking sentence:

“ISO 6346 height marks are mandatory for containers with an actual height greater than 2,6 m (8 ft 6 in). UIC Class 2 and Class 3 height-width pictograms are governed separately by Table 1 and UIC Code 592.”

If the 2,6 / 8½ example is retained, it should not be presented as the principal mandatory ISO 6346:2022 height-mark example. A nominal ISO 668 2 591 mm / 8 ft 6 in container is not higher than 2,6 m [S1] [I1].

Loading Method 9.2 states: “For Ct’s longer than 8 ½’, in addition to the height indication, there is a black/yellow marking on the corner pieces” [U1]. In this context, “longer” should be “higher”. The phrase “on the corner pieces” is also less precise than ISO 6346:2022.

ISO 6346:2022 requires the alternating black/yellow stripes on the top members of each end frame and side wall at each corner adjacent to the corner fitting, with a minimum length of 300 mm / 12 in, visible from the ground or from the top [I1].

Suggested replacement wording:

“For containers with an actual height greater than 2,6 m (8 ft 6 in), ISO 6346:2022 requires a height mark on both sides and alternating black/yellow stripes on the top members of each end frame and side wall at each corner adjacent to the corner fitting. The striped area is to be at least 300 mm (12 in) long and visible from the ground or from the top.”

This is a wording alignment only and does not affect Table 1 or the Method 9.2 loading logic.

On method page 3-4, the examples 24G1, 3CT6 and 4LH2 are introduced on a line labelled “Container Height” [U3]. Technically, these are ISO 6346 size/type codes. The first two characters form the size code, and the following two characters form the type code [I2].

The example calculations themselves are aligned: Table 1 uses the second size-code character for the width/height case, while Table 2 uses the first size-code character for the length case [U2] [U3]. The point is therefore only the label.

Suggested label:

“ISO 6346 size/type code:”

The following line could also be clarified from “which correspond to:” to:

“UIC Table 1 codification result:”

This preserves the existing C-code results, including 24G1 → C 29, 3CT6 → C 12 and 4LH2 → C 331 [U3].

UIC Loading Guidelines, Volume 2 Goods, Version 01/04/2026, 10th edition

• [U1] Loading Method 9.2 – Containers, method page 1-4: marking examples, mandatory-marking sentence and black/yellow stripe sentence.
• [U2] Loading Method 9.2 – Containers, Table 1, method page 2-4: ISO Class 1 dimensional-code cases, 2 591 mm / 8 ft 6 in height value, h > 2,6 m condition, Method 9.1 routing and UIC Class 2 / Class 3 pictograms.
• [U3] Loading Method 9.2 – Containers, method page 3-4: Table 2 and example lines showing 24G1, 3CT6, 4LH2 and the corresponding C-code results.

ISO 6346:2022 – Freight containers – Coding, identification and marking

• [I1] Clause 6.2.4 and Annex F: height marks for containers higher than 2,6 m / 8 ft 6 in, including Annex F height-mark format and black/yellow stripe requirements.
• [I2] Clauses 5.2.2 and 5.2.3, with Annexes D and E: size-code and type-code structure.

ISO 668:2020 – Series 1 freight containers – Classification, dimensions and ratings

• [S1] Clause 5 and Table 2: Series 1 external dimensions, including the 2 591 mm / 8 ft 6 in and 2 896 mm / 9 ft 6 in height classes.

UIC Code 592 OR – Intermodal Transport Units, Minimum Requirements

• [M1] Appendix A.3.1: distinctive marking for containers of Classes 2 and 3; upper group for height in metres, lower group for width in metres, and no m abbreviation on the marking.