Rakes of the old freight wagons, classified 'CG', for Covered Goods, consisting of the old 4-wheeled C or CR wagons) up to 1850 or so tonnes (2350t for some types of wagons). With the introduction of bogie stock, mixed CRT/CRC/BCX rakes became more common and brought the maximum up to 2750 tonnes. As noted above, even today the standard load for a typical shipment by a 'full rake' of miscellaneous goods is about 2200t.
The introduction of bogie wagons and air-braked stock has allowed larger and heavier formations to be hauled, and 3660t rakes of box wagons became common. The so-called 'Jumbo' rakes, consisting mostly of BCX and similar bogie stock are up to 3500-3750 tonnes (these are air-braked today, but vacuum-braked rakes of this size have been used), and beyond these are what are known in IR parlance as 'Super-Jumbo' rakes, carrying up to 4500-4700 tonnes. The super-jumbo rakes consist entirely of the newer BCX/BCN/BCNA/etc. wagons and are air-braked.
The 'Green Arrow' rakes have only BCN/BCNA wagons, up to about 40 of them. The name comes from the green paint scheme used for these air-braked wagons. Forty BCN wagons are about the limit for most parts of IR's network because of the restriction imposed by the lengths of loops where freight trains can be diverted to allow passenger trains to pass. The standard loop length is 650m, although many places are now getting loops of 900m to cope with freight formations that are up to 850m long.
BOXN formations up to 58 cars are also common (again, this is the maximum length allowable on most loop lines). The 'Green Bullet' trains have BOXN rakes usually carrying a bulk commodity like iron ore for thermal power plants. (The ones carrying coal are often known as 'Black Bullet' trains.) BCNA rakes can be up to 58 cars too, but more commonly 40+ cars or so. BCN wagons being a bit longer, only 40 cars or so are formed into a single rake.
In several places, IR has run, as experiments, longer freight trains formed by combining two or three freight rakes for part of a route and then splitting them later as they go on to their respective destinations. However, when running combined the extra-long rake has to be scheduled carefully as it places severe constraints on the movement of all other traffic on the same track because it cannot fit on any loop at any station, and any problem with the rake can result in major delays.
Upgraded versions of the BOXN wagons (class BOXN-HA, see the section on wagons) with payloads of 66t (and axle loads of up to 23.5t are planned to be run on several sections after track upgrades. Sixteen sections have been identified for this [4/05]: