loading vs trainload

loading and trainload both are nouns.

Word	Noun	Adjective	Verb	Adverb
loading	Yes	No	No	No
trainload	Yes	No	No	No

As nouns, trainload is a hyponym of loading; that is, trainload is a word with a more specific, narrower meaning than loading:

loading (noun)	trainload (noun)
the labor of putting a load of something on or in a vehicle or ship or container etc.	quantity that can be carried by a train
goods carried by a large vehicle
weight to be borne or conveyed
a quantity that can be processed or transported at one time
the ratio of the gross weight of an airplane to some factor determining its lift