You did not say what kind of locos you were planning for your mixed trains.
The problem with heavy grades is not the power source but the robustness of your locos. I use a pair of B'mann shays and they pull heavy trains up stiff grades (using battery power). I have seen a similar shay pull 28 cars up a 150 foot 4% grade at Dave Goodson's when I visited a few years ago - and of course, he uses battery power.
A Connie would not budge 28 cars on a 4% grade and is quite likely to strip gears.
Now, if you plan to double head SD-70s you can pull some really long trains ... but charge up some heavy duty D cells for the job.
Regards ... Doug
The problem with heavy grades is not the power source but the robustness of your locos. I use a pair of B'mann shays and they pull heavy trains up stiff grades (using battery power). I have seen a similar shay pull 28 cars up a 150 foot 4% grade at Dave Goodson's when I visited a few years ago - and of course, he uses battery power.
A Connie would not budge 28 cars on a 4% grade and is quite likely to strip gears.
Now, if you plan to double head SD-70s you can pull some really long trains ... but charge up some heavy duty D cells for the job.
Regards ... Doug