Note 75 — Chapter VI · THE ATMOSPHERIC SYSTEM. A.D. 1840—1848. ÆTATIS 35—43.
Reading edition
It must be borne in mind that all the inconveniences attending the use of auxiliary locomotives must be encountered, or else the excessive dead weight of an engine powerful enough to take a train up the steepest gradient in a hilly district must accompany it for the whole length of that part of the line.