There are two main trends. The first trend is towards higher productivity by increasing the carrying capacity of railcars. And the second trend is for greater speed.
UWC’s Deputy CEO for Scientific and Technical Development and Head of the All-Union Research and Development Centre for Transportation Technology
Choosing between weight and speed
What trends are we seeing today on the world market for railcars?
There are two main trends. In transport of bulk goods, like coal, ore and crushed stone, the trend is towards higher productivity by increasing the carrying capacity of railcars. The USA, Australia and South Africa are designing heavyweight cars with axle loads between 32 and 40 t. At present Australia is the leader in this field – the Australians are experimenting with cars that have 40 t axle load. If these cars show good technical and economic performance, other countries with heavyweight rail freight will follow Australia’s example.
The second trend, mainly in Europe, is for greater speed. Freight car design is getting closer to that of passenger cars. Speeds of up to 120 km/h are now standard for freight trains in Europe, while countries with heavyweight traffic are still at maximum speeds of 80 km/h. Greater speed is an alternative way of making freight traffic more cost effective, and it also helps to synchronise freight and passenger operations.
Are European customers more interested in speed?
Absolutely. The greater part of rail freight in Europe is container traffic, so the main type of rolling stock is flat cars. The main efficiency indicator for that type of transport and what makes it competitive with road transport is speed.
But, looking objectively, you get the impression that European railways haven’t decided yet which way they will go. Some of the cars now in service have axle load of 25 t and speeds up to 100 km/h, while others have 22.5 t loads at speeds of up to 120 km/h. It’s not clear which of these will win out and rolling stock manufacturers are building both types of cars.
There is heavyweight traffic on some limited sections of the European rail network – in places where coal or ore is transported. Sweden and Norway are increasing axle loads: the Kiruna-Narvik and Kiruna-Lulea lines, between the mine and the ports, were designed from the start for axle loads of 30 t and after three years of monitoring the load has been stepped up to 32.5 t. But that only applies to a few routes where heavy loads are usual. And they are unusual for the European network as a whole.
Would it be fair to say that in Russia we have both trends: development of heavyweight traffic for bulk cargoes and increase of speeds, particularly for container transit between Europe and Asia?
Yes, we have to address both issues. The efficiency of bulk transportation grows with increase of carrying capacity and volume of the car, but typical track construction (particularly bridges, etc.) puts limits on the extent to which axle load can be increased, and it will take a lot of time and money to modernise or replace infrastructure. To keep within regulatory limits for impact on track and bridges, axle load must not exceed 27 t. Cars with that axle load are now being used on the Sverdlovsk Railway and their impact on infrastructure is being monitored. Use of 27 t axle load on lines with limited capacity is another step towards the development of heavyweight traffic in Russia.
Mixed cargo and passenger traffic on the same tracks is a driver for equalising the speeds of cargo and passenger traffics. Cars on the latest bogies, such as the 18-9855 model (built by UWC) could travel at up to 100-105 km/h with 25 t axle load assuming that the track was in good condition. But the actual state of the track doesn’t permit speeds above 80 km/h for freight trains. So the main thing that needs to be done in order to increase speeds is to improve the infrastructure. Freight cars are ready for higher speeds today.
Heavy haul transport in Russia. Monitored operation of UWC gondola cars on bogies with axle load of 27 t
Different solutions for different markets
You said that in Europe freight car construction is getting closer to construction of passenger cars. How does that work?
Most of all it relates to bogies. For example, in the UK they have a long-standing system of track access charges based on impact on the track and, in order to reduce that impact, design of freight bogies is getting closer to that of passenger cars: double spring suspension1, disc brakes2, use of non-metal elements for supporting the car body on the bogie frame3, and work is being carried out to reduce unsprung mass4 by the use of lightweight wheel sets. We are seeing a similar trend in continental Europe, but there is a lack of clear economic incentives for creating track-friendly cars.
A lot of work is being done on new brake systems for freight cars that run at high speeds. Double brake shoes per wheel are standard for Y25 bogies used. Further increase in braking efficiency can be achieved by the use of disc brakes. Electrical and electronic control systems are being developed to reduce the brake response time.
Strict requirements for noise reduction are another important factor for railways in Europe: they pass through densely populated areas, so much attention is paid to reducing levels of noise pollution from rolling stock. Noise-absorbing coatings are being developed for wheels and wheel sets, brake pads use materials that do not squeal when the brakes are applied, elastomer bushings and gaskets are being installed in car suspensions to prevent knocking (elastomers are good at absorbing high sound frequencies due to their viscosity – Editor’s note).
- Spring suspension on bogies consists of all the elements that provide elasticity (leaf and coil springs, shock absorbers, vibration dampers) and ancillary components (spring suspensions, rollers, brackets, etc.), which connect wheel sets to the frame or body of the railcar. Spring suspension affects the running performance of the car and reduces the dynamic impact of the track on the car and the car on the track. Suspension can be single (primary or secondary) or double (both primary and secondary), depending on the number of consecutive connected systems of elastic elements. Double suspension gives smoother oscillation of the car, empty or loaded, compared to single suspension.
- Compared with shoe brakes, disc brakes offer more efficient braking, especially at high speeds (160 km/h and above), prevent overheating of the wheels, abnormal impact on wheel surfaces, etc.
- Non-metal elements in the side bearings between the body and the bogie frame suppress lateral rolling.
- Unsprung mass is the mass of all parts of the bogies located below the suspension (wheelsets, adapters, frames, brakes, as in the 18-9855 bogie manufactured by UWC).
What are the other specific requirements for railcars that exist in different markets?
The railway industry is very conservative, and as a rule all of the safety requirements for rolling stock and components are clearly spelled out in the standards. Many countries follow the standards of the Association of American Railroads (AAR), which are quite close to Russian standards. Europe previously followed standards of the Union Internationale des Chemins de Fer (UIC, International Union of Railways), but they are now being replaced by the new system of European Norms (EN). UWC is monitoring all these changes. When we start work on the design of a new car, we don’t just take account of the standards, which are in place now. We also try to forecast possible changes during the period of project implementation (i.e., in the next one or two years). We can do this because UWC is a member of the AAR and has a permanent subscription to EN standards, so we take part in the public review of new documents or amendments to existing documents.
As well as meeting safety standards, we have to take full account of the specific requirements of our rolling stock customers or requirements imposed by the railways where the rolling stock will operate. These usually refer to suitability of the cars for loading and unloading infrastructure, and aspects of maintenance and repair.
One recent UWC’s export project was for hopper cars to transport bauxite in Africa. What were the design challenges in that project?
This was a typical example of a project carried out to AAR standards. Naturally, we also took account of features that would optimise performance of the cars in the African climate. What is important for Russian customers is tolerance to cold, but what matters for a customer in Africa is reliability of the braking and loading equipment at high temperatures and high levels of humidity. Another important thing was to make sure that the loading and unloading system on the cars would be compatible with existing infrastructure. We even designed a special rig for testing performance of the lower discharge hatches.
Initiatives are always welcomed
What other major international projects has UWC implemented recently?
There is a special excitement about work on foreign projects
We have a major partner programme with North American companies. Our partner is Wabtec Corporation, a global supplier of high-tech products for railways. Tikhvin Freight Car Building Plant (TVSZ, UWC’s production centre) won access to the North American market last year after completing a certification procedure by the AAR. We are now producing and supplying large-size castings to design drawings by Wabtec: side frames and bolsters. We started with a few dozen casting sets per month, and now we are supplying hundreds of sets per month. The American market appreciates the quality of our products, which are made at TVSZ using V-process molding, and the number of our North American customers is growing steadily.
We have another large American customer, the company Trinity, to which we supply various individual components for freight cars. These products don’t require certification. They include various assemblies and components that can be produced at the request of a specific customer at an attractive price.
Our engineering centre is always pleased to work on export projects. The staff are highly qualified and a lot of them have experience on markets with standard gauge, and not just in the ‘‘1520 space.’’ They are a young team and very keen on new projects, which help them to improve their skills, develop and get familiar with the latest technologies. There is a special excitement about work on foreign projects.
Can you give a few more details about the Sggrs80 articulated container flat car, which will be presented at InnoTrans 2018?
As I already said, Europe has high volumes of container transport and articulated container flat cars are increasingly popular because they make it possible to achieve full load capacity and therefore maximise economic efficiency (the containers themselves are rather lightweight).
The Sggrs80 model (European railcar designs are designated by letters, unlike the Russian system, which uses numbers – Editor’s note) can carry various load types. It is an 80-foot flat car, so it can accommodate two 40-foot containers, or four 20-foot containers, and heavy containers can be placed at the ends, distributing the load on the outermost bogies. This car can also be used for transporting swap bodies (20 to 40 feet long).
What is special about our design is that we have adapted the frame structure to match manufacturing equipment at TVSZ, which has a high level of automation and robotics. We prepare steel sheet ourselves for making profiles and angles. As a result the frame has best-possible quality, complying with all European welding standards.
We will present the articulated flat car for the first time at the InnoTrans exhibition. It is our own design, created on the basis of an analysis of the market situation in container business and the needs of European carriers. The car is specially made for 1435-mm gauge, and comes in two variants – with 25 t axle load and maximum speed of 100 km/h, or 22.5 t axle load and maximum speed of 120 km/h. We expect the second variant to find the most demand in Europe.
The Sggrs80 articulated container flat car is getting ready for shipping to InnoTrans 2018 (The Tikhvin production site, August 2018)
What are the prospects for articulated cars in Russia?
For Russia, we are designing articulated gondola cars, hopper cars and tank cars as well as articulated flat cars. Their advantage is that you can carry a larger cargo mass for the same train length than with standard four-axle cars – you increase the load per unit of length. Articulated car technology has been tried and tested in the USA, where they sometimes use up to five articulated sections (not just two). Six-axle articulated cars, with two sections and a shared bogie in the middle, have proved most efficient in Russia and Europe.
There have been several attempts at manufacturing articulated cars in Russia, but they were unsuccessful due to lack of the necessary regulatory framework. The first successful project was implemented by Russian Railways jointly with Tatravagonka (a major manufacturer of rail freight cars for the European market, located in Slovakia – Editor’s note). A small batch has been manufactured and is being operated and closely monitored. All the necessary regulatory mechanisms have been put in place as part of this project, so we now have an understandable procedure for implementation of articulated cars and it will be possible to develop this sort of rolling stock further.
Is that something UWC plans to do in the near future?
As a first experiment, we have run an articulated gondola car to Far East ports with loading and unloading operations. We hope to complete the work and proceed with closely monitored operation of articulated gondola cars, flat cars and hopper cars next year.
Are cargo owners and operators interested in this project?
Yes, these cars have good technical and economic specifications, so the project attracts the audience. And not just in Russia, but also in other countries with 1520-mm gauge.
What are the prospects for transportation using swap bodies?
European-style swap bodies are not fully suited to Russia. In Europe, they have very small dimensions – width and height of the body are limited by the narrower 1435-mm gauge. Also, European swap bodies are intermodal, i.e., they are designed for use in both railway and sea transport. For Russia, we are now working on a technology for specialised railcar swap bodies that would allow us to fully exploit the wide-size specification (Tpr clearance diagram) and the loading height that our standards allow. So it is the same technology, but with much greater load and volume capacity, which should be suited to axle load of 25 t. It is possible that our technologies for specialised swap bodies with enhanced technical and economic performance will be of interest to European customers as a way of improving the cost efficiency of flat car transport.
What progress has there been in the use of new materials?
We have a major research programme for the use of new materials and we are developing technologies to improve the performance of components made from traditional materials. For example, we were the first to use surface-hardening technology on the production line to improve the wear resistance of automatic coupler parts, and of centre-plate castings5. Surface hardening works faster than an anti-wear welding and further grinding.
Another successful application of new materials is the use of ductile iron with spheroidal graphite in the friction parts of bogie suspensions6. We have installed isothermal hardening equipment at the Tikhvin Plant, which produces ductile iron with a Brinell hardness over 500. In Russia monitored operation of cars with friction wedges and side bearings made of ductile iron have shown that they last for more than one million km, which is a very good result in any market, including the USA and Europe. Our bogies also use ultrahigh molecular polyethylene7, which does not deform under long-term static loads and is effective in protecting friction surfaces from wear. We are considering application of this material in other aggregates and components.
In tank cars, we have replaced wooden bars, which were previously used as supports for the tanks of railcars, with special polyurethane bars that enables more accuracy in assembly work at the TikhvinChemMash production facility (part of UWC holding). Research and development is an ongoing task. Some of the best solutions, which offer the biggest efficiency gains, are found “unexpectedly,” in the course of implementing orders.
- Surface hardening is applied when the part is close to completion. A hardened part has a more robust surface and better resistance to wear. The part also goes through additional volumetric heat treatment to make it less brittle after hardening. This makes the part highly resistant to wear on its surfaces that are exposed to friction, while the rest of its metal remains sufficiently elastic to withstand impact loads.
- Ductile cast iron differs from ordinary cast iron because it contains graphite inclusions with spherical shape. This gives very high strength and performance properties (hardness and wear resistance).
- This material has high strength, wear resistance and impact viscosity in a wide temperature range, from -200 to +100OС, as well as very high chemical resistance to aggressive environments.