user: Question: What is the sum number of years where the wheel arrangement of 0-4-0t?
Columns: ['IWCR No.', 'Name', 'Wheel arrangement', 'SR No.', 'Year made', 'Year withdrawn']
Types: ['text', 'text', 'text', 'text', 'real', 'real']
Sample row: ['1 (1st)', 'Pioneer', '2-2-2T', '—', 1861.0, 1904.0]
SQL:

assistant: SELECT SUM("Year made") FROM "Table" WHERE "Wheel arrangement" = '0-4-0t';