Small engines vs. Big grades...

I recently realized that a section of track near where I live had an imposing 1.26% grade. This is interesting to me because it answers why trains on the line always seemed overpowered. In the days of steam however this branch was always operated by small steam engines, mostly moguls, consols, and ten wheelers. I have no pictures of any steam locomotives being used on the line that even had trailing trucks!

About how many cars could a smaller steam locomotive be trusted with to tackle such a grade? What would the difference between the milk trains and coal trains which once roamed the line? How long could a passenger train be if it were thrown at the grade?

Thanks for any replies.

First question: how long is the grade? Is it even a trainlength? Even if it is, say, a mile long, momentum can make a big difference.

But with no momentum a 40000-lb-TE engine should manage 1000 tons or thereabouts.

On the shortline Bath & Hammondsport, steamers with small drivers could handle the grade uphill to Bath (about 1% at its steepest). However, when their steamer went into the shop for repairs, the B&H often had trouble with "loaner" they got from Erie. Apparently most of Old Reliable's engines had bigger drivers for faster speed, so even 2-8-0s had a hard tome on the B&H. BTW, trains were usually a dozen freight cars or less.