CREATE TABLE table_80044 ("Units" TEXT, "Type" TEXT, "Period used" TEXT, "Formed from" TEXT, "Trailers" TEXT)

Name the typed for formed from 6-pul trailer third in res unit
SELECT "Type" FROM table_80044 WHERE "Formed from" = '6-pul trailer third in res unit'
SELECT "Type" FROM "table_80044" WHERE "Formed from" = '6-pul trailer third in res unit'