Why were Crabs called Crabs???

[Frellis]

I have often wondered this on many occasions.

In the blurb you get from Bachmann with their model it says that the name was derived from the ungainly pincer-like cylinders and valvegear layout. It also says this in Brian Haresnape's Fowler Locomotives book.
But after extensive looks at photos etc. I can't see how this can be.

I think it was because the engines crews reckoned the machine to be so good that it could even go sideways. (but obviously didn't).

What do you think?

I'm interested to hear your theories.

Cheers

FRED

[andrewtoplis]

Possibly with such large outside cylinders they would have swayed from side to side when steam entered each cylinder...hence crabs?

[arabiandisco]

Because they were no good for going forwards?

[alexnick]

Because they were no good for going forwards?

or backwards?

[davvydo]

because of the curved shape of the running boards

or because they were/are a bit tempremental and made the crew crabby !

[ianmacmillan]

The name CRAB was unknown in central Scotland.

Railwaymen always called them Moguls.

[davidaward]

Another explanation I've heard is that the safety valves are alongside each other rather than behind each other on the boiler- so they go sideways.

There's no dount about they were fantastic locos in the right hands though, they were more powerful with more guts to them than the stannier design which was a development of them, but with not as good riding qualities. The sheer power of the cylinders on the crab used to make them pitch from side to side when working flat out!

[cua193]

Apparently they were designed with almost horizontal cylinders & had to be re-designed when it dawned on someone that the cylinders wouldn't clear platforms.

The inclined cylinder reminded someone of a crab walking with its claws raised - hence the name.