UP AC4400CW 6848Palemon MO Palemon

Is there a limit on how many locos they can run together?

@Kempy72 - Not really. In recent practice, however, locos are not necessarily all online in such consists unless topography along the planned route warrants using extra power. Computerized "Trip Optimizers" now make such decisions in many cases. On the really large power shuffles with all locos (up to 12 or even more) and no trailing freight, only a few locos are likely to be active in the string. The only practical limit to operational power in such large consists is the strength of the couplers vs. the weight of the train being pulled. Distributed power is what has made the idea of two-and-three-mile-long freights feasible, reducing the stress of excessive power at the front of the train. The train above was a minimum of two miles long, and had two more units as DPU power assisting farther back.

Wow, that’s a lot of motive power!