4-6-0+0-6-4

Under the Whyte notation for the classification of steam locomotives by wheel arrangement, the 4-6-0+0-6-4 is a Garratt locomotive. The wheel arrangement is effectively two 4-6-0 ten-wheeler locomotives operating back to back, with the boiler and cab suspended between the two swivelling power units. Each power unit has two pairs of leading wheels in a leading bogie, followed by three coupled pairs of driving wheels and no trailing wheels.

4-6-0+0-6-4

Equivalent classifications UIC class 2C+C2 French class 230+032 Turkish class 35+35 Swiss class 3/5+3/5, 6/10 from 1920s Russian class 2-3-0+0-3-2

First known tank engine version First use 1912 Country Brazil Railway Mogyana Railway Designer Beyer, Peacock and Company Builder Beyer, Peacock and Company

A similar wheel arrangement exists for simple articulated locomotives, but is referred to as 4-6-6-4. On a simple articulated locomotive, only the front engine unit swivels while the rear unit is rigid in relation to the main frame.

Overview

This was a rare wheel arrangement for Garratt locomotives, with only seven locomotives built for two South American customers.

• The first was for the metre-gauge Mogyana Railway of Brazil, with five examples built by Beyer, Peacock and Company in 1912 and 1914.
• The other was two locomotives built for the 3-foot gauge Ferrocarril Pacifico de Colombia by Armstrong Whitworth in 1924.

4-6-0+0-6-4 Garratt production list – All manufacturers

Gauge	Railway	Works no.	Units	Year	Builder
3 ft	Ferrocarril Pacifico de Colombia	565-566	2	1924	Armstrong Whitworth
1,000 mm	Mogyana Railway, Brazil	5529-5530	2	1912	Beyer, Peacock
1,000 mm	Mogyana Railway, Brazil	5787-5789	3	1914	Beyer, Peacock