Given the following context:

Around noon, General Henry Abbot arrived at President Street with a battalion of 99 to 114 engineers. As the group advanced toward the armory of the 6th Regiment where they were to be quartered, they were met by a crowd of 500. Jeers from the crowd turned to missiles until one soldier, Private Corcoran, was struck in the head and wounded. Abbot gave orders that his men were to halt and fix bayonets, at which point the crowd scattered.Throughout the day and the previous, as many as 500 new special police were sworn in, doubling the size of the police force. Each was provided with a star, a revolver and espantoon. The recently arrived regulars brought the garrison of federal troops in the city to between 700 and 800. The vessels Powhatan and Swatara had also been ordered to the city, along with their 500 marines.News reports recalled court held that day in the southern district, where 195 charges of riot and 17 charges of drunkenness were resolved. That night the city was quiet. A telegram was dispatched from Adjutant General Edward D. Townsend to General Hancock, who had just arrived in the city earlier that day. He was directed to move his men to Pittsburgh, where riots were ongoing.

answer the following question:

What rank were the people who were to be quartered? 

engineers