Bill Post has shared a detailed historical account regarding the use and purpose of the Fog Pressure Units deployed by the Chicago Fire Department in the early 1960s. The Fog Pressure Units were introduced to provide a quick, effective water stream to control fires before traditional engine companies could connect to a hydrant and deploy a canvas line. These units were especially useful in areas with limited access, such as expressways, alleys, and locations near railroad embankments, where conventional fire apparatus struggled to maneuver. They also served as a valuable tool in neighborhoods with poor hydrant coverage or unreliable water supply. Between 1961 and 1966, when the Fog Pressure Units were acquired and put into service, the Chicago Fire Department had only around 11 or 12 engine companies equipped with booster tanks. The department had not purchased any new engines for nearly a decade, from 1955 to 1966. The last batch of engines acquired were ten 1956 B model pumpers, each featuring a 200-gallon booster tank. A few older models were later retrofitted with similar tanks, but this was rare. Each Fog Pressure Unit was equipped with a 300-gallon water tank and two narrow-diameter hose reels. They featured specialized fog nozzles that produced a fine mist under high pressure, hence the term "Fog." The first unit was built on a Willys Jeep chassis with a John Bean pump, while the rest used International Harvester chassis with Darley pumps and custom bodies. While some units were stationed near expressways, most were located in high-risk districts on the west and south sides of the city. Fog Pressure 2 was based at O’Hare Field, using the original Willys Jeep unit. These units were also assigned to the Snorkel Squad companies, offering tactical flexibility and additional capacity for personnel and equipment. In 1964–1965, three extended-body Fog Pressure Units were specifically purchased for the Snorkel Squads. As newer engines with 500-gallon booster tanks began entering service in 1967, many Fog Pressure Units were reassigned or retired. By 1970, all but two had been decommissioned. Fog Pressure 2 remained at O’Hare Field, and Fog Pressure (SS1A) continued to serve with Snorkel Squad 1. Most units were taken out of service between 1968 and 1969, including those assigned to Snorkel Squads 2 and 3, which were disbanded in 1969. As mentioned in a previous post, Fog Pressure 31A was temporarily stationed at Truck 31’s new location for over a year until Engine 64 moved in. At their peak in 1966 and 1967, the department operated twelve Fog Pressure Units (not counting the three assigned to the Snorkel Squads). However, within just two years, nearly all were retired, leaving only the exceptions noted above. Bill Post Tower Type Breaker Hammer,Car Removal Shears,Hydraulic Clamp,Grab Bucket For Excavator KingKong, Intelligent Equipment (Xuzhou) Co., Ltd , https://www.impimaq.com