LNER J17 Coupling Rod Query

[t-b-g]

I am currently working on a set of frames for a J17. On looking up some photos to see if the knuckle joint in the coupling rod was in front of, or behind, the centre crankpin, I was a bit bemused to see that there isn't one. The similar GER 0-6-0 classes have the same rod arrangement.

 

I am no GER expert but I bet we have one or two on here, so the question is, were the coupling rods jointed and if so, where was the joint? Was it on the centre crankpin just like we modellers do?

 

It is the first time I have noticed rods on a 6 coupled loco without any sign of a visible joint so I am intrigued.

 

Tony

[Pebbles]

Articulated on the centre crankpin. This applies to the J18,19,19/2,J20 and B12, although the early B12s did have an additional joint in the vertical plane. Can't think of any others; it certainly doesn't apply to the J15.

[t-b-g]

Articulated on the centre crankpin. This applies to the J18,19,19/2,J20 and B12, although the early B12s did have an additional joint in the vertical plane. Can't think of any others; it certainly doesn't apply to the J15.

 

Many thanks.

 

Just like most etched kits then!

 

I wonder why it was not more widely used as it would seem to be a simpler system with fewer moving parts than the more conventional separate joint.

 

Cheers,

 

Tony

[LMS2968]

I suspect it involves the surface area in contact with the crankpin, which must either be only half the normal per rod, or the pin extended to allow each rod the same area.

 

The LNWR did this with its eight coupled locos, with the inermediate rod outside the leading and trailing. It's more symetrical with an eight coupled loco than a six coupled, though.

[Sweedy]

The J17 had longer pins for the central wheelset. The joint was a forked joint with the front coupling rod having the fork and the rear being plain ended.

[Pebbles]

If you want detail you can do no better than the drawings published by the Great Eastern Society.