Most of the text for this profile was provided by William Snook.

Freightliner Heavy Haul broke into the UK coal traffic market with a contract for Enron and an initial order was placed with Greenbrier (Wagony Swidnica) of Poland for 55 bogie coal hoppers. The first of these rather lengthy (19.6m) wagons was delivered in November 2000. Externally the bodywork was very similar to the 1995-built JMA hoppers used on the coal circuits by National Power, and the hopper body was in unpainted metal with large Freightliner logos. Solebars were green and bogies black. Within a few months, additional wagons were ordered bringing the total first to 250 then finally to 446, with about 200 delivered by the end of 2001 and the fleet completed in December 2005. More orders were later placed but to a revised, shorter design (HXA, q.v.).

The wagons were coded HHA-A, however in 2002 the design was changed with revised braking capacity, and the hand brake wheel now mounted on the body rather than the bogies. Wagons 370250 onwards were to the revised design and had TOPS code HHA-B. All HHAs have a 73.5 tonne capacity, 4 automatic bottom discharge doors and are fitted with Network Rail approved 'track friendly' bogies.

It would appear that the type has in fact undergone several minor changes, judging by the design codes. The first wagon was to design HH001A, but details of later arrivals are a bit sketchy. However, by 2008, almost all of the HHA-As were to design code HH001K and the HHA-Bs were to HH001M, apart from the last 34 which were to HH001Q. Design codes are normally assigned sequentially (eg, HH001A, then HH001B etc), suggesting that a large number of codes had been introduced then superseded, presumably as a result of successive minor technical improvements.

These wagons were in the headlines in February 2001, when they were involved in the tragic accident at Great Heck near Selby. A passenger train was derailed following a collision with a car that had crashed off the road bridge. This was then struck by a Freightliner coal train heading in the opposite direction. The coal train was formed of 16 nearly-new HHA wagons, these being most of the first production batch (370002-370018) and eight were damaged beyond repair.

Freightliner soon had an advantage over rival EWS who were still using a large fleet of MGR hoppers with a smaller 32 tonne capacity, which meant more wagons and higher maintenance costs. As Freightliner's slice of the coal market grew so did the HHA wagon fleet but there was an issue regarding the length, which caused operating problems with restricted siding lengths at some terminals and short goods loops. When EWS introduced their 102t HTA coal hoppers a year later in 2001 they were only 17.8m long, giving EWS an advantage in competition. To combat this Freightliner introduced a slightly better-designed coal hopper, this being the HXA, of which an initial 109 were ordered. Delivery of the new shorter wagons started in late 2006. Despite being one metre shorter, they were able to carry the same payload as the HHA. Eventually, 219 of these HXA wagons were built, giving Freightliner a bogie coal wagon fleet in excess of 600 vehicles in seven years.

Increasing environmental concerns and the introduction of a 'carbon tax' in 2013 led to an unprecedented decline in the use of coal for power generation. This resulted in the mass withdrawal of many coal hoppers with wagons being stored across the country in places like York, Leeds, Telford, Barrassie and Guide Bridge, to name but a few.

Some of the coal hoppers saw reuse on other flows and on 22nd April 2017, 56078 took 18 HHAs to South Wales for a short term contract moving dredged sand. The train ran from Neath Abbey wharf in South Wales, running overnight to the Leeds Stourton RMC terminal in West Yorkshire. The contract lasted with Colas until the July of that year and then went dormant. In 2018, the train restarted with GBRf and ran to the Washwood Heath Tarmac site that was under construction. The last train noted to have arrived there was in 2020, however the train ran a handful more times in 2022 but with HYA wagons instead.

Conversions were explored for the growing biomass traffic, generally limited to the fitting of opening top covers to existing hopper wagons. Freightliner had HHA coal hopper 370058 modified by WH Davis in late 2011. The HHA-C TOPS code was assigned to 370058, along with design code HH001L, but it was destined to remain unique. The wagon was later returned to its original form and remains in storage at York North Yard to this day.

Freightliner green livery has been applied to just two HHA hopper wagons in place of the original bare metal finish. Wagons 370029 and 370035 were modified at York in 2015 for use as coupling adaptor wagons for the delivery of class 387 EMUs and later class 197 DMUs and Mk5 coaching stock. At one end of each wagon, the buffers and existing drawgear was removed and replaced by a Dellner type coupling. A new TOPS code of HHA-D was issued for these conversions, along with design code HH001R. When in use, the wagons were often accompanied by unmodified (and un-repainted) HHA wagons to act as brake force runners. Eight wagons have been recorded as being allocated to the same pool as the adaptors (pool 9412), these being 370008, 370020, 370033, 370034, 370161, 370188, 370195 and 370227, although three of these have since been moved into pool 9990, indicating they are in storage.

In October 2015 it was reported that 64 HHAs were to be scrapped by C F Booth of Rotherham, with the bogies recovered to be reused under new box wagons. Some of these wagons were stored at Margam, where scrapping of the bodies began, albeit slowly, in 2022, with the cutting finishing in late 2023. The bogies and some other components were sent to Poland and fitted to new-build MWA box wagons 81.70.5891.001-064, these being delivered to the UK between May and August 2016.

Rather than scrap more redundant wagons, VTG decided to repurpose some into aggregate hoppers (VTG had become the owners of the HHA fleet when they bought wagon lessor CIT (NACCO) in 2017). However, as stone is more dense than coal, a solution was found in reducing the size of the wagon. The centre section of the wagon was cut out and the two end sections welded back together in a process that is commonly referred to as 'cut and shut'. Horizontal beams were also added to reduce the impact on the doors when loading. W H Davis was contracted to undertake 100 rebuilds, the first of which appeared in late 2019. The rebuilt wagons retained their original numbers with new codes of HHA-E and HH003A (it is not clear why HH002A was skipped), and all were previously HHA-Bs from the number range 370251-370436.

To summarise, as of early 2024, from the 446 HHAs built, 229 have been scrapped, 100 rebuilt as aggregate wagons, 7 in use for barrier traffic and 110 remain stored.