Saturday, August 25, 2012

R739 - Operating Breakdown Crane


What a lovely word - "operating". You don't see it much on modern model railway products but put simply, it means you can play with them.

The breakdown crane set has been in the Hornby catalogue since 1971 and is preceded by a metal version from Hornby Dublo. The set includes a crane, two riding trucks and a match truck. The jib can be raised by turning one of the knobs on the side, slews by swinging it by hand and finally another knob lifts the hook.
You might think it's all a bit toy like but the model is surprisingly realistic. The most obvious error is that on the real thing, the chimney hinges backward to clear tunnels and bridges. The model version is fixed in place.
The other change is more subtle and clever - on the prototype, cables handle the lifting. The model employs chains for the same task. Anyone who has even built a model crane will understand why. Model cables don't behave like real ones. They are always too stiff. Even with a big, heavy, cast hook, you find it difficult to keep any tension. Chains on the the other hand flex properly and hang nicely.  Those RTR wallahs are cleverer than many railway modellers give them credit for.
Fortunatly for real railwayman, these cranes were operated by steam rather than giant, knurled knobs, as shown in this lovely diagram from the days when childrens publications bothered to try and explain technical stuff.

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