BBB Steam Loco Basics

[Brickthus]

I've posted some pics of basic steam loco chassises using BBB wheels.

http://www.brickshelf.com/gallery/mbellis/...s_0-6-0_top.jpg

http://www.brickshelf.com/gallery/mbellis/...-6-0_bottom.jpg

http://www.brickshelf.com/gallery/mbellis/..._0-10-0_top.jpg

http://www.brickshelf.com/gallery/mbellis/...10-0_bottom.jpg

One reason for this is that I can now re-use the wheels in a more complex MOC :-)

There's an 0-6-0 and an 0-10-0, both using the blind drivers to get round curves. This is a bit different from my UK Class 14 shunter, which has synchronised pivoting wheels and extending rods! http://www.brickshelf.com/cgi-bin/gallery.cgi?f=121842

Mark

8mm scale Trains gallery: http://www.brickshelf.com/cgi-bin/gallery.cgi?f=62749

[SavaTheAggie]

Be careful, though. Spreading your flanged drivers as far apart as on the 0-6-0 example and the BBB wheels may begin to act funny when going through switches, hitting the rail guides and whatnot. Any further apart and they'll definately start having problems.

Also be careful with that 0-10-0, I call that the 'daisy cutter' configuration, since any part of the train beyond the blind drivers will cut down anything along the outside of curves. :)

--Tony

[Commander Wolf]

Personally I prefer not to use blind drivers and articulate my wheelbases instead.

Though the cosmetic difference is ultimately not terribly significant, the use of more smaller bogies tends to let the locomotive run smoother, subsequently reducing wear on motors and other moving parts.

Just personal preference, though; I know most people probably prefer their solid bases.

[SavaTheAggie]

If you don't mind me hijacking/adding to the thread topic...

Here is a slightly more advanced design

http://www.flickr.com/photos/savatheaggie/330679435/

This design is for Pacific and other types of wheel arrangements where the pony truck has four wheels, and you don't want to have to alter your pistons or use smaller wheels for the pony truck. The rear pair of pony truck wheels have been fixed to the rest of the locomotive, so that the locomotive turns on one flanged pair of drivers and the one pair of small wheels.

--Tony

[Brickthus]

Be careful, though. Spreading your flanged drivers as far apart as on the 0-6-0 example and the BBB wheels may begin to act funny when going through switches, hitting the rail guides and whatnot. Any further apart and they'll definately start having problems.

Also be careful with that 0-10-0, I call that the 'daisy cutter' configuration, since any part of the train beyond the blind drivers will cut down anything along the outside of curves. :)

--Tony

I made sure to smooth off the BBB wheels because moulding points on the flanges can catch on the curves. For a 3'9" wheel (BBB in 8mm scale) the wheels are usually no further apart than 6ft on a real steam engine. Since there are no larger BBB wheels, there is, fortunately, no reason for me to put flanged drivers further apart!

Since I model to 8mm scale, I have a much wider loading gauge than 6-wide builders. Mine is 5 studs either side of the sleepers on the curves and 14-wide in total on the straights, so daisy-cutters are no problem within reason. I altered the design of my LMS 2-6-0-0-6-2 Garratt engine http://www.brickshelf.com/cgi-bin/gallery.cgi?f=116053 to reduce overhang, by allowing the train motors to pivot between the raised driving wheels. The Pendolino http://www.brickshelf.com/cgi-bin/gallery.cgi?f=77379 still overhangs by 5 studs on the outside of curves.

My rolling stock (up to 80 studs long) goes right over the lever frames on switch points, which is why I use different motorised http://www.brickshelf.com/cgi-bin/gallery.cgi?f=230517 and pneumatic http://www.brickshelf.com/cgi-bin/gallery.cgi?f=147934 mechnisms and have abandoned the yellow levers. This also allows a bit more room for working valve gear rods on steam engines. The curves themselves are spaced out with straights - 2 per curve on the main line and 1 in the yard.

Mark