2-4-6T

Diagram showing 2-4-6 wheel arrangement; front of locomotive on left.

In Whyte notation, a 2-4-6 is a steam locomotive with two unpowered leading wheels followed by four powered driving wheels and six unpowered trailing wheels. This wheel arrangement is only documented as being used for tank locomotives; no 2-4-6 tender locomotives are recorded. ^[1]

Equivalent classifications

Other equivalent classifications are:

• UIC classification: 1'B3' (also known as German classification and Italian classification)
• French classification: 123
• Turkish classification: 26
• Swiss classification: 2/6

The equivalent UIC classification is 1'B3' (or (1'B)'3' for a Mason Bogie).

Examples

This unusual wheel arrangement does not appear to have been used in any country except the USA. ^[1] The following railways are recorded as having used locomotives with this wheel arrangement: ^[2]

• Pennsylvania Railroad: one locomotive built by Altoona in 1882
• Wisconsin Central Railroad: one locomotive built by Burnham, Parry, Williams & Co in 1887
• Boston, Revere Beach and Lynn Railroad: two locomotives built by Mason Machine Works in 1892 ^{[3] : 111–112}
• Illinois Central Railroad: ten locomotives built by Rogers in 1893
• Adirondack and St. Lawrence Railroad: one locomotive built by Schenectady in 1893

References

1. "2-4-6 Locomotive Data by Country" . Retrieved 14 November 2025.
2. "2-4-6 Steam Locomotives in the USA" . Retrieved 14 November 2025.
3. Stanley, Robert C. (1980). Narrow Gauge - The Story of the Boston, Revere Beach & Lynn Railroad. Boston Street Railway Association.