CREATE TABLE table_50731 ("BR No." TEXT, "Lot No." FLOAT, "Date" FLOAT, "Built at" TEXT, "Boiler type" TEXT)

What year is the date when the boiler type is forward topfeed, the built at is Crewe, and lot number is less than 187?
SELECT COUNT("Date") FROM table_50731 WHERE "Boiler type" = 'forward topfeed' AND "Built at" = 'crewe' AND "Lot No." < '187'
SELECT COUNT("Date") FROM "table_50731" WHERE "Boiler type" = 'forward topfeed' AND "Built at" = 'crewe' AND "Lot No." < '187'