The prototype Brush type 2, class 31, Diesel electric locomotive.
The Triang class 31 was based on the Brush type 2, later class 31 Locomotive. The prototype class 31 had a complicated history, with various engine changes and design upgrades. Some class 31’s remain certified for main line use today. All photos the author except the electric blue loco.
The class 31 was made by Brush Traction of Loughborough. Production commenced in 1957 and continued until 1962. The first batch of 20 locomotives, numbered D5500–D5519 are recognisable as having no headcode box.
The long lived X.337 motor and chassis was used for this locomotive. later models had pickups on the trailing bogie. However, this unit has several issues, if not maintained. More on this later.
The model (R.357) was first released in 1962 with the experimental electric blue livery. The Triang class 31 continued in production until 1976. In 1963 the livery changed to the familiar BR green. By 1968 BR blue was in use. D5572 was the number used for most of the models production run. D5578 was used for the Electric blue version in 1962 and a re-release in 1966.
The BR green and blue versions are quite common and you can get good examples from about £20. However, the rarer electric blue version is £40-£70.
The BR green livery had the later crest and yellow ends. The paintwork is neatly applied with a slightly glossy finish. The handrails were moulded to the body and painted silver, the paint tends to rub off, over the years. Bogie detail is fine for the era. The buffers are plastic and not sprung.
The front detail is sparse, however the cab is glazed. A head code box is provided and is nicely printed. Representation of the roof fans is crude.
The later, trailing bogie pickups can be seen below. The bogie wheels are insulated at one end.
The mechanism is a bit growlly but can perform well if properly maintained. The power bogie only has four wheels. It is fitted with magnadhesion, however, this only works with steel track.
Chassis running issues – how to service the mechanism.
It is easy to reassemble this chassis incorrectly and cause a short circuit. Check with the photographs below if you think it may have been messed with, before applying power. Confirm that the insulator is on one end of the brush spring (the blue thing in the image below). Check that the pickups are inside the wheels, not on top of the flanges.
The main issue with the x.337 chassis is wheel bearing wear. This can cause the gears to go out of mesh and jam up. Oil the nylon bushes at each end of the wheel sets. Check that the gears are not worn or missing teeth. New and, or re-profiled wheel sets are available on Ebay. The earlier gears were made of white nylon.
The armature bearings can also wear, check that there is no “slop” in them. Clean the “com” on the armature with lighter fluid and replace the brushes if necessary.
Another issue is overheating and melting of the plastic “spider” that holds the brushes. Check that there is no bulging melted plastic near to the top of the brush, where the spring is.
Overheating can be caused by a tight mechanism, so lightly oil all the moving parts. The bogie sides act a heat sink and should not be to hot to touch after running for a while.
The comprehensive video below looks at repairing a similar mechanism.