How many constructions has a Wheel arrange- ment of 4-4-0?
CREATE TABLE "equipment" (
  "builder" text,
  "construct_tion_no" real,
  "date_ordered" text,
  "wheel_arrange_ment" text,
  "s_cylinder" text,
  "engine_weight" text,
  "tc_st_l_no_1883_84" real
);
SELECT SUM("construct_tion_no") FROM "equipment" WHERE "wheel_arrange_ment"='4-4-0';