CB10 (wagon power and visual effects) ...
TTDPatch Version: 2.6 r1825 (any)
Patch Feature: Callback 10
Using 0x00 .. 0x0F as callback result does not use visual effects as per veh prop 19 (traction).
With veh prop 19 (traction) set to 0x08 [diesel] and 22 (visual effects) to 0x40 [no effects]; then a cb10 result of 0x00 .. 0x0F displays steam and not diesel smoke.
Note : for more information also see FlySpray OpenTTD bug report #FS1855 [http://bugs.openttd.org/task/1855]