Freightliner has a proud history of setting the standards for innovative and sustainable wagon solutions in the UK

On the face of it, wagons that carry intermodal containers are simple – a flat, skeletal platform with container fixing points at each corner. Upon closer scrutiny, however, there are many complexities in optimising a seemingly simple concept:

  • Unlike other wagon types that are usually either tare or fully laden, the intermodal wagon must be capable of carrying an infinitely variable weight between its tare and maximum gross load and not be over or under-braked in any state. An under-braked vehicle will threaten a train’s mandatory stopping distances, whilst over braking can lead to wheel damage and excessive compressive forces down the train.
  • In order to carry shipping containers, the wagon’s ability to ride smoothly and precisely control sway and curve overthrow must be exact.
  • Shipping containers can be 20ft, 30ft, or 40ft long, and some short-sea and domestic containers might be 45ft or even 53ft long. So, the fixing points for the container pockets need to be flexible and accommodate various loads.
  • Today’s environmental and sustainability standards require constant pushing. So, the wagon needs to be light to reduce train dead-weight and ideally optimised to reduce aerodynamic drag.
  • The wagons must be capable of travelling at speeds that are compatible with a rail network that is shared with passenger trains. They must be optimised to carry as many containers per unit length to fit into the passing loops on the UK network and travel at speeds between those passing loops so as not to delay passenger trains.
  • The intermodal wagon must deploy new technologies that minimise wear from heavy and fast freight on both the track and the wagon itself.


The existing UK intermodal wagon fleet is made up primarily of historical wagon designs, configured around 60ft platforms that were designed to carry single-stacked 8’6” high containers on the British Rail standard freight gauges. In the 1980s and 1990s, British rail and Freightliner developed ‘low platform’ wagons that can carry 9’6” high by 40ft long containers in the same clearance diagram. Over the time that these wagons have been in operation, both the freight clearance diagram and the container mix have evolved as follows:


  • The containers moved by maritime customers have migrated from predominantly 20‘long, 8’6” high containers to a mix of 40’ long, 8’6” high and 9’6” high containers and a much smaller residual 20’ container demand. The migration has been sufficiently significant that there is often an inability to sell the 20’ space on a 66’ wagon to a customer, so the train runs with an empty space.
  • The aforementioned growth in 9’6” containers has impacted the ability to load the container on a “standard wagon” (typically with a deck height of just below 1000 mm), with the taller container fouling the clearance diagram.
  • All ‘low platform’ wagon designs harbour significant design compromises. These wagons necessitate small wheels that have low rolling inertia, resulting in a propensity to slide and become damaged under braking. They also require a ‘well’ between the bogies to accommodate the container, which means the wagon must be 70’ long and will only accept a 40’ container between the wheels, compromising the number of containers that can be loaded in a given train length.


In response, Network Rail infrastructure investment programmes over the last 15 years have steadily lowered tracks under bridges or tunnels (or raised bridges and tunnels over the tracks) to increase the clearance diagram to predominately W10, meaning that today a ‘standard height’ wagon can accommodate a 9’6” high container over the majority of the core intermodal freight corridors.

As a result, in 2004, Freightliner commissioned a wagon capable of carrying 40ft containers to maximise the number of containers in any given train length. These first wagons took time to develop, and economic pressures during the financial crisis of 2008 and 2009 delayed their arrival to market until 2014, when Freightliner became the first operator of the VTG Ecofret 40’ wagon. The early designs were ballasted to improve vehicle ride and ensure their resistance to derailment in all loading conditions was uncompromised.

As the first Freight Operating Company to develop standard 40ft high platform wagons and the first to introduce the 40’ Ecofret wagon, Freightliner has a proud history of setting the standards for innovative and sustainable wagon solutions in the UK.

Deloitte recently calculated that rail freight generates £2.45 billion in benefits to the UK economy each year, including over £1.6 billion in productivity gains  for businesses and over £800 million in social benefits, including environmental, congestion and safety. Deloitte also developed a framework for valuing a path on the network, which could be used to inform decision-making over capacity allocation. They calculated that a path for an intermodal train is worth up to £1.5 million per year.

As the largest freight operator of electric locomotives in the UK, Freightliner is committed to driving forward decarbonisation, which is at the heart of their strategic focus and aligns them directly with customer expectations. Freightliner is leading the way in exploring, developing and delivering innovative solutions to reduce their carbon footprint even further, including reductions in locomotive idling times, longer trains, locomotive efficiency upgrades and a hydrated vegetable oil trial. They have also secured government funding for both a Freight Energy and Emissions Calculation tool as well as the development of a dual-fuel solution for the Class 66 locomotive.

As well as a 40’ wagon improving aerodynamic drag by increasing load density over a long freight train, it is important that the wagon is as light as possible to reduce the amount of ‘dead weight’ on the train. The dead weight of the wagon will remain for its useful life of typically 40 years, and every tonne of dead weight will contribute to years of carbon emissions. So, Freightliner was unwilling to accept the compromise of a ballasted wagon as a solution to the vehicle ride issue and set a unique challenge to industry partners Greenbrier Europe and Wabtec.

Freightliner has worked with Greenbrier and its European team based in Wagonyswinica, Poland, for over 20 years, having produced over ten wagon designs and constructed more than 1,400 wagons for use in the UK and Europe. Greenbrier is a tried and tested partner with a focus on innovation, quality, customer service and value that has become synonymous with its relationship. Similarly, Freightliner has launched four new designs of track-friendly bogies with Powel Duffryn, Probotec, SCT all now owned by Wabtec.

The teams responsible for this innovation are largely the same people that Freightliner has dealt with over the last 20-year period. The project team was given the challenging target to deliver a new wagon design for the business, optimised for fuel efficiency and low maintenance and, unlike any other 40’ wagon, to achieve full gauge clearance with a 9’6” container across the W10 network. The new FFA-G wagon delivers full W10 network clearance using modern low track force bogies with a class leading tare weight of just 18.5t, whilst meeting all the applicable European and UK standards. It cannot be stressed enough how important it is to have the right people on a project team and to ensure that they all work and communicate together, sharing their combined wealth of expertise.

It’s not just a case of assembling experts – the FFA-G project team had to be able to collaborate well and deploy creativity in navigating the challenges. As any experienced Engineer will tell you, whilst doing something new is exciting, it’s also fraught with challenges and the odd surprise or two. The FFA-G project had a new bogie, new underframe, new demanding safety standards and of course… a ‘new normal’ as Covid-19 swept the globe.

With Freightliner leading the project, Greenbrier set about as wagon designer, builder and system integrator, whilst WABTEC focused on delivering the new designed bogie and on vehicle derailment resistance and ride.

Freightliner also selected its preferred certification and assessment partner, TUV Rhineland, to make sure that the wagon met all mandatory vehicle acceptance and safety standards. The complex gauging work required to get the vehicle route clearance on the network was led by D Gauge with support from Network Rail. In practise, all the parties were heavily interdependent on each other to get the design right.

The starting point for the project design phase was to carry out research on existing wagon types and operations to see what lessons could be learnt. Freightliner has a long history of operating intermodal wagons and, as such, has a wealth of knowledge deep within its businesses. With safety and ease of maintenance in mind, the Freightliner project team engaged widely throughout their Engineering Maintenance, Operations and Safety teams. For example, the FFA-G, unlike some intermodal wagons, has a split inter-vehicle coupler to allow platforms to be separated safely during in-the-field maintenance.

The decision to include this option was made directly following feedback from Freightliner’s in- the-field maintenance teams. The folding 20ft spigots were designed based on wider experience gained from other intermodal wagon types, ensuring they are reliable and durable over the vehicle’s life. Positioning and access to key maintenance components was carefully considered to minimise maintenance down-time wherever possible.

Before detailed design could commence, the project had to create its Authorisation strategy. For this it was necessary to understand not only what methodologies and standards were available and applicable, but also which path to go down, as there is more than one way to obtain Authorisation. Working with partners TuV Rhineland and in consultation with the ORR, the Authorisation strategy was agreed at the top of the project, where it would then shape all proceeding tasks.

With the loading gauge a critical requirement, from the outset the project team engaged with gauging specialists at D Gauge and Network Rail to ensure that the wagon could achieve this challenging target with the new TF20 low track force freight bogie. The suspension characteristics and vehicle dimensions were carefully selected, and preliminary vehicle models were run over the virtual W10 network before any designs were committed. This ensured that, with a working deck height of 980mm, the FFA-G wagon could achieve route acceptance for the entire W10 network with a 40ft, 9’6” ISO container.

Also critical was the demonstration of vehicle ride and resistance to derailment. The wagon was fully tested and met the requirements of ride standards EN14363 and GMRT2141 Iss 4 at the Velim Test facilities in the Czech Republic. This included the new and previously unseen and untested UK requirements to physically demonstrate resistance to derailment with offset container loads applied. There was much activity on all sides to ensure that all involved understood the new requirements and that the testing was designed and performed to demonstrate the wagons performance against them.

Due to Covid, there was very little opportunity for any of the team to visit the wagons during testing, adding to the challenges. The new requirements to demonstrate compliance with cyclic top, would be later demonstrated via modelling software with the now validated model.

The FFA-G wagon is just the latest contribution to Freightliner’s strategy. With the clear aim of improving rail’s environmental benefits further, the FFA-G has been designed with fuel efficiency in mind, being two-and-a-half tonnes lighter than its nearest competitor, incrementally meaning that an additional two per cent of carbon emissions are saved in a train of FFA-G wagons than other rail services. The modern low track force bogies ensure that noise levels are reduced to a minimum.

The FFA-G wagon further leverages the environmental benefits of rail, achieving 78 per cent saving of carbon per gross tonne moved over road and an even greater contribution to bringing all greenhouse  gas emissions to net zero by 2050.