What's your favorite engine's slowest scale speed?

My Bachmann On30 4-6-0s can creep so slow that you can't immediately tell they're moving at all, sometimes. I have zero complaints about their slow-speed handling.

Ironic that as kids, we're all about how fast they'll go, but when we're older and still into model trains, we're likely going to want to know how slow they'll go!

Well since the MTH Galloping Goose top speed is 30 smph, climbing up a huge hill on various layouts it has run it sounds cool when the engine noises gets luder while climbing.

All of my MTH and Sunset/3rd Rail steam locomotive models will operated at "walking speed", just like a real steam locomotive.

My MTH creep along at 2 - 3 spmh, my Lionel legacy crawl at almost unseen fractions of an MPH. Wicked cool from both.

Two of my favorites are my Railking Pennsy 4-8-2 M1a and NYC 0-6-0 switcher, they'll creep along at 1 scale MPH.

Ogaugeguy,

      My Lionel Legacy B6 switcher will crawl around my clubs layout at speed step 1 all day long. It is amazing to watch and listen to. No hesitation or shuttering, smooth as silk.

Oh the smoke is great too.

JohnB

I think the slowest movers I have are the Vision Line Genset and the Legacy B6.  Both will crawl along at less than 1/2" a second. 

I like the Vision Line PRR CC 2. It just creeps along and each chuff is strong and loud, and the bell just swings in step with the engine, great smoke effects, just like a steam engine should...

The VL BB where one can see and hear each individual smoke stack puffing a strong amount of steam at a very slow crawling speed, whether this is scale or not, for me it is very satisfying...

Not a direct answer but many of the posts eluded to it. Even my small Legacy steamers have a prototypically correct "heft" to them as they move around the layout due to the smooth running characteristics and slow speed. 

I've run several of my Lionel Legacy steam locomotives at very slooooow crawl. Maybe 1/32" A second. Impressive!