These carry two kilometers of 75 mm hose and one (or sometimes two) 1000 LPM portable pump(s) - used to boost pressure on longer hose runs and/ or those which involve steep grades which incur greater pressure losses. Most German fire services are still content to rely on 75 mm hoses for water relays, although many other European countries prefer larger diameters.
Added by Rob Johnson on 21 October 2023.