Table: locomotive_info
Columns: 1st_built
1913_class
w_a
no_built
builder
date
lner_class

Question: What is the 1913 class of locomotive that has a 1st built value under 494 and WA of 4-4-0t?
SQL: SELECT "1913_class" FROM locomotive_info WHERE "1st_built" < 494 AND "w_a" = '4-4-0t'