Question: What is the max speed of the unit with an 8+4 quantity built before 1971?
SQL: SELECT SUM("Max Speed (km/h)") FROM "2-1527960-3" WHERE "Quantity built" = '8+4' AND "Year built" < 1971.0;

Question: What is the numbers of the THN unit with a power greater than 220?
SQL: SELECT "Numbers" FROM "2-1527960-3" WHERE "Power (horsepower)" > 220.0 AND "Type" = 'THN';

Question: What is the power of the unit built after 1995?
SQL: SELECT SUM("Power (horsepower)") FROM "2-1527960-3" WHERE "Year built" > 1995.0;