I am re-listening to the wrath of the khan podcasts by Dan Carlin, and checked out the wikipedia article for the Mongol conquest of Khwarezmia. Both of these point out the addition of siege engineers and equipment from China to the Mongol Armies, I wonder how did this affect the famed mobility of the Mongols? Did it not nullify their speed to have to wait for battering rams etc. to be hauled along?
Also, during a campaign like this, do we know how many miles could a Mongol army cover in a day? Thanks!
I can't speak to the engineers themselves, but according to Hugh Kennedy's "Mongols, Huns, and Vikings," the Mongols usually built siege engines onsite. Timber was sometimes an issue: he mentions that, at the siege of Alamut, the local orchards were used to make trebuchets. Ammunition could also present problems: some areas lacked good stones, so at some sieges they had to be hauled from several days' journey away. Kennedy mentions one siege where wooden ammunition was used. (133)
This was in contrast to some contemporary rulers, as Kennedy mentions. The Mameluke Sultan Baybars, ruling around 1260, "used to transport his engines from one siege to the next, either whole or in kit form" (133) as he campaigned against the crusaders.
Hope this answers at least part of your question!
Source:
Kennedy, Hugh. Mongols, Huns and Vikings: Nomads at War. Edited by John Keegan. London: Cassell, 2002.
Edit:
Forgot to provide page numbers! My apologies.