What Bachmann calls their Anniversary Edition 4-6-0, "Annie", and is usuall sold by itself without cars, comes with metal rods and a different chassis than the Big Hauler 4-6-0, which often come in sets but are sometimes available individually.
The 4 Big Hauler 4-6-0 I have all came in sets & I bought them because they were sets; 3 with a pair of passenger cars each; one with a reefer and caboose.
The 1 Annie 4-6-0 I got was sold in a very long box by itself.
Mine of each of the above which were bought with disability settlement lump sum back pay in 2009 and 2010 are a different generation than the current new release Anniversary 4-6-0, which also advertised as having a different tender than the generation I bought.
Metal gears are standard in the new "Annie" from what I've read.
About valve gear, the Bachmann 4-6-0 which show no outside valve gear are correct in being that way as they represent locomotives with Stephenson style valve gear which worked off eccentrics mounted on the axles.
Probably for price point reasons, since molding parts and applying parts costs money, Bachmann omits the external arm and rod to the steam valves in the square chests on top of the cylinders; those parts can be seen in various arrangements on various real 4-6-0 of the era.
The large scale Spectrum series 4-4-0 and 2-6-0 which I have seen do have those details included.
I don't consider either the Big Hauler 4-6-0 or the Annie 4-6-0 to be 'toys', as they are not at all designed to be pushed around the family room carpet. They will do fine on track laid on that carpet, but they truly do belong on rails.
Their body castings did in fact originate years ago as what I would class as a toy, a battery operated remote control version with non-conductive plastic wheels.
The boilers are bulky because of the need to accommodate a number of flashlight batteries.
Used with the same deliberate care applied to O and HO trains, and also not overloaded with dozens of cars to pull, they will do fine.
And their design has served my purposes in that the Big Haulers are basic models which those of us who enjoy adding details can have a lot of fun with.