Sentence:  In order that these very important mails might not be unnecessarily delayed, we procured an express engine, and having, as is customary in such cases, fastened those for Manchester and the North on a <WSD>larry</WSD> between the engine and the Post-office, they being too bulky to travel in the latter, we departed at 8.10, [...] On our arrival at the next station, Crewe, we were much alarmed at the intelligence received from the engineer, that one of the bags on the <WSD>larry</WSD>, which proved to be the Carlisle, was on fire: [...] 
Meaning of the word marked with <WSD> tags:  A large, low, horse-drawn, four-wheeled wagon without sides; also, a similar wagon modified for use on railways.