A lot of historical knowledge attached to railway truck (5)
I believe the answer is:
lorry
'truck' is the definition.
(I know that truck can be written as lorry)
'a lot of historical knowledge attached to railway' is the wordplay.
'a lot of' means to remove the last letter (most of the word but not all of it).
'historical knowledge' becomes 'lore' (traditional learning).
'attached to' says to put letters next to each other.
'railway' becomes 'ry' (abbreviation for railway).
'lore' with its last letter taken off is 'lor'.
'lor'+'ry'='LORRY'
(Other definitions for lorry that I've seen before include "Commercial vehicle" , "From which stolen goods fall?" , "Large truck" , "HGV" , "Heavy goods vehicle" .)