[SlateCreek]

If you're doing the Mt. Washington cog, there is no transition ... the equipment is all cog, all the time. Jeff Damerst at www.shawmutcarshops.com has built a few MWCR cog engines, generally wheel powered tenders pushing the loco model .... the cog in this case would be strictly decorative. A couple of traction tires on the tender and you might have enough to shove one car up a steep grade.... but I doubt you'd be modelling Jacob's ladder!

Matthew (OV)

 

[SlateCreek]

Oh, and as an afterthought ... eaglewings ironcraft makes a cog system.
http://www.eaglewingsironcraft.com/view_item.php?img=./img/grp/cog.jpg&desc= COG - Straight modules $15/linear foot. 4 ft Transition Ramp (not more than 25 degrees) $105. 5 ft-diameter curve 90 degrees $75. 5 ft-diameter curve 45 degrees $45.
And, as you can see, they have transition ramps and all that.
Matthew (OV)

I think the link may work better as:

http://www.eaglewingsironcraft.com/view_item.php?img=./img/grp/cog.jpg

If not use www.eaglewingsironcraft.com and it's under "Bridges."