Table: steam_locomotive_specs
Columns: class
firebox
cylinder_size
valves
valve_gear
number_built
years_built

Question: What was the cylinder size of this engine that was made with only 88 pieces?
SQL: SELECT "cylinder_size" FROM steam_locomotive_specs WHERE "number_built" = '88'

Question: What was the engine class that was built on 1906-08?
SQL: SELECT "class" FROM steam_locomotive_specs WHERE "years_built" = '1906-08'

Question: How many engines were built with a cylinder size of 20 ½” x 26”, firebox is belpaire and valve gear is from Stephenson?
SQL: SELECT "number_built" FROM steam_locomotive_specs WHERE "cylinder_size" = '20 ½” x 26”' AND "firebox" = 'Belpaire' AND "valve_gear" = 'Stephenson'

Question: This engine with a cylinder size of 20 ½” x 26” and a firebox of radial-stay was built when?
SQL: SELECT "years_built" FROM steam_locomotive_specs WHERE "cylinder_size" = '20 ½” x 26”' AND "firebox" = 'Radial-stay'

Question: How many types of valves were used on this engine that was built on 1902-05?
SQL: SELECT COUNT("valves") FROM steam_locomotive_specs WHERE "years_built" = '1902-05'