Tuesday, August 26, 2014

Crane tank wheelies

Crane Tank

Sharon and Daryl ask:

Did you manage to get the southeast fine cast crane tank working without it doing wheelies?

Be grateful for some help if you have any tips to get it working.

They have obviously been reading the Melbridge Dock rolling stock page where I mention the propensity this loco has to pull a wheelie when moving forward.

It's all an issue of weight distribution. This is a whitemetal loco with the rear wheels only 5mm away from being in the centre of its length. Worse, the hefty cab and bunkers are over or behind the rear wheels whereas the lightweight boiler and chimney are on front.

Add in to the mix the low gearing forced on the design by the need to cram a tiny motor and gearset in the low-slung boiler and it's all looking a bit bad with a potential for jack-rabbit starting.

To counteract this, I've added some lead behind the front bufferbeam and although the manufacturer supplies a slug of whitemetal for the smokebox, I replaced this with lead shot as well.

Apart from that, there's not much you can do apart from use a quality controller and ease away gently. The careful driver will keep all four wheels on the track.


Paul B. said...

This is a common problem with whitemetal OO9 loco kits. Replacing the cast cab roof with one made from plasticard would help, if your really keen the rear cabsheet could be re-made in platic as well.

Phil Parker said...

Good point. It's a simple change - far easier than re-building the entire cab, but it would give a significant weight loss at the back end.

If only all weight loss was so easy!

James Finister said...

Paul B beat me to it, but I suspect it would make a massive difference, but strength might be an issue. If you replaced the whole cab with brass it would look a lot better as well.

Paul B. said...

A virtually identical crane tank saw service at Hodbarrow heamatite mines in Cumberland. Named Snipey, it was built by Nielson in 1890, its apparently preserved, but not on public display, in Lytham-St-Annes.

This is a kit that I'd like to build one day, but with a High Level gearbox for super slow running.

James Finister said...

A picture of Snipey, mentioned by Paul B can be found here http://mikemorant.smugmug.com/keyword/hodbarrow;tank;lytham/