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Track engineers look to get more from materials and possessions

01 Jun 2006

As well as giving exposure to the latest technologies, the triennial exhibition of track maintenance equipment organised by the Association of German Railway Engineers (VDEI) provides an opportunity to reflect on industry trends. Exhibits focus on getting the most out of material and track possessions, finds David Burns

CERTAIN CONCLUSIONS can be drawn from the list of 160 exhibitors at this year's IAF exhibition of track maintenance equipment taking place in Münster on May 29 - June 1.

Major suppliers are consolidating. Many small suppliers have improved their machines or products, but do not have resources for developments that will make a major impact. The emphasis appears to be on getting the most out of the existing track, and maximising the work undertaken in a track possession.

The European scene changed significantly with the separation of operations from infrastructure and the beginning of concessioning. Though governments have retained ownership of the infrastructure, contractors now undertake an increasing amount of maintenance and renewal work. While some buy very expensive plant, contractors are usually unwilling to take a risk on a major new machine, and so the technology being exhibited at Münster is evolutionary, not a quantum leap.

Not many North American companies are exhibiting, but those that are attending reflect the current situation. Until recently the Class Irailroads barely earned their cost of capital, so the emphasis has been on getting the most life out of track investment.

Databases and inspection

A major trend in both Europe and North America is the increase in inspection and analysis. There are four aspects to this, which can be covered by a sampling of exhibitors.

The foundation for track and structure maintenance is a comprehensive database containing age, condition and geometry. One of the better examples on show will be Zeta-Tech's Maintenance of Way Information System (Mowis), which lies behind a suite of 12 inspection, analysis and planning models.

In contrast to the large inspection machines that weigh tonnes, there are several tools weighing a kilogramme or so which can make manual inspection easier and more meaningful.

The need to replace sleepers is a function of defect type and clustering. Track inspectors can use Zeta-Tech's TieInspect handheld computer to input data on sleeper condition directly to a database. The computer analyses this in relation to the type of train service, calculating how many new sleepers are needed and where.

Any quality assurance engineer will tell you that it is critical to have a check list with specifications when undertaking manual inspections. Zeta-Tech has gone one better with its TrackInspect and SwitchInspect PDAs, which provide a detailed menu of inspection steps, and require the input of specific railway-defined measurements and observations. The device gives a numeric condition rating, immediately flagging violations of standards, and stores the information for historical trending.

Track and rail inspection contractor EurailScout has recently developed equipment to replace walking inspections with high-resolution digital video cameras. On show in Germany will be the VST-05, which produces tapes for later review in the office, allowing track inspection to be done in 10% of the time formerly required and without the dangers of staff walking on the track.

When it comes to maintenance planning, the rate of track geometry deterioration is one of the most important data sets that a railway can compile. It is vital that measurement be frequent and fast, especially on heavily-used main lines, and ImageMap has solved this problem by developing an optical measurement system that can be installed in passenger trains. In addition to being fitted to many of the world's track geometry measuring cars, it is also installed on French TGV trainsets.

High speed trains need track that is accurately levelled and aligned. Historically, measurement to the required accuracy was a manual operation reliant on fixed track markers. Not only was this labour-intensive, but the 'fixed' markers had a tendency to move.

Plasser & Theurer will have details of its EM-SAT120, which provides totally automated measurement. It can measure track geometry to within 1 mm and, given current GPS technology, absolute track location can be calculated to within 10 to 20 mm. Optional features can measure ballast profile and, using ground-penetrating radar, determine ballast condition. Correction data can be electronically transferred to a following tamper, and all this at up to 7 km/h.

Maximum rail use

One of the most significant current trends is in the use of rail. Years ago, some railways based rail changes purely on age, with no regard for traffic. Today, with rail costing $600 to $800 per tonne and the need for increasingly heavier sections, rail is an expensive investment and it is important to make it last as long as possible.

North American railroads used to cascade rail twice, but today, with fewer secondary lines to cascade to, main line rail is often worn until it is ready for scrap. This is only possible with frequent inspection for profile and defects. Eurailscout's UST02 Rail Inspection Train is capable of inspection at 100 km/h, using ultrasonic and eddy current detection in multiple channels.

Years ago, catenary geometry was observed by a man looking out of a window in the roof of a specially-designed coach. For obvious reasons, the speed was restricted and accuracy left much to be desired, and this is clearly not an acceptable approach for high speed lines. It is very difficult to measure catenary to the accuracy required, and do it fast enough to avoid track congestion. DB Systemtechnik's white light measuring system and ImageMap's coach body compensating and rail reference system have been combined, creating a catenary measurement system capable of high speed recording of wire height, stagger and wear.

Data must be analysed once it has been collected. Zeta-Tech will be demonstrating a series of software models which take the raw data and convert it into risk, prioritising immediate maintenance or repairs by using a series of broken rail, track buckling and vehicle/track geometry models. From this, maintenance and replacement needs can be projected.

Work planning

There are two types of work plan. Macro programmes run for several years, while micro programmes plan individual track possessions. Long-term planning models are available for most aspects of track and structure maintenance, one being Zeta-Tech's RailLife forecasting model.

Once a decision has been made for what work is to be undertaken, the question is how best to organise the possessions. With a continuing decrease in the length of possessions, the answer can be found using software such as Possession Optimisation for Track Maintenance (SOG), developed by the Institute for Transport, Railway Construction & Operation in Hannover and due to be demonstrated in Münster. This optimises the use of track machines, and assists with correcting the problems which are bound to occur.

You have the perfect track. Now let's make sure it's not going to deteriorate faster then necessary. Besides rain, there is little more destructive to track than out of round wheels, flat spots, slewed bogies, and overloaded wagons. So when the train is running at over 100 km/h, how do you catch the 'trouble-makers'?

Tamtron Systems is exhibiting what it considers is the answer. Developed from its weigh-in-motion technology, the Scalex Wild System measures destructive forces by means of load sensors capable of collecting 240000 samples per second, enabling the inspection of a passing wagon or coach while it is travelling at 250 km/h.

Nothing dramatic?

There are few dramatic innovations this year. Perhaps fewer organisations are willing to risk financing revolutionary ideas, but there are still interesting improvements or developments.

Getting staff to the worksite is usually a problem; getting tools, machines and material there is an even bigger problem. Over the years the ganger's trolley has developed into a sophisticated machine. One of the latest is the Robel 54.24 Track Vehicle, capable of carrying a large crew, their tools, and material to any work site. It can also be adapted for other tasks, including plowing snow and inspecting bridges. What appears to be unique is that they can operate in multiple to haul up to 2600 tonnes.

Getting ballast in the right quantities in the right place used to be a time-consuming task. Today, Plasser & Theurer's BDS2000 profiles the ballast, collects any surplus using the plough and brushes, and carries it to locations where addition is required.

First there was the single-sleeper tamper, then the two-sleeper tamper, next the continuous action tamper, then the three-sleeper tamper. Now we have the four-sleeper tamper. Plasser & Theurer is introducing the Dynamic Tamping Express 09-4X. Everything about this machine is impressive. It tamps four sleepers simultaneously with a high degree of accuracy, follows with dynamic stabilisation, and all at an incredible average of 2600m/h. If track possession time is at a premium, this machine really is a significant development.

At the same time as increasing the production speeds of tamping and track renewal machines, Plasser &Theurer has been working to increase the performance of its ballast cleaners. The latest RM800 Super3S machine operates at 1500m3/h.

The RM800 solved the problem of ballast screening capacity by having two screening boxes on a separate vehicle. The Super3S has three screening boxes, increasing capacity by a further 50%. The excavation width can also be remotely varied from 3·7 to 5·3m using hydraulic rams.

One of the more difficult tasks on an active railway is the replacement of turnouts. This process was significantly improved with the development of Desec's Turnout Replacement Machine about 15 years ago. The Finnish firm will be displaying the latest version of the machine, the TL70, that can install a 40m long turnout weighing 36 tonnes.

Urban grind

Maintaining the contact surface is key to maximising rail life, and grinding the surface is the most important aspect of this task.

Speno International will exhibit three grinding machines. The SRR16M-1 is an 'urban' grinder specifically designed for the physical constraints of small clearances, tight curves and steep gradients. The RR16MS-2 switch grinder has the latest trolley and measuring systems, and RR24MB-15 is a main line grinder with a modular design, so several can be coupled to maximise production within a given possession.

There are many manufacturers of small machines, but one company seems to produce almost the whole range. Robel has just introduced what will become a trend, small machines with four-stroke engines. These are quieter and produce lower emissions than two-stroke engines, which are no longer allowed in some countries. The first machine to have a four-stroke engine is the Robel 13.44 Rail Milling Machine, capable of milling on a 2400 mm reference base and thus giving a more accurate surface after the rail or switch point has been repaired.

There are a number of track maintenance and repair operations that require a series of small machines working consecutively, leaving the operators open to the elements, and with limited lighting at night. The innovative Robel Mobile Maintenance Unit allows operators to work in an environment that is safe and protected from the weather, with good lighting. It also reduces physical strain, as the workers do not have to manhandle the machines on and off the track.

Finally, the continuous action tamper was a generational jump in the tamping of track. Both Matisa and Plasser & Theurer have taken the technology one step further with continuous action machines that can tamp both track and turnouts, and have the capacity for lifting concrete sleepered turnouts.

Matisa will be exhibiting the B66 UC, a single-sleeper machine based on its high-output B66U. Plasser & Thuerer's Unimat 09-32 4S Dynamic is a two-sleeper machine which incorporates a Dynamic TrackStabiliser. Plasser & Theurer is also exhibiting the Unimat 09-475 4S, which in addition to the features of the 09-32 has an additonal CAL-SAT measuring system.

  • Picture caption: EurailScout's VST-05 Video Inspection Car has several high-resolution video cameras which capture front and rear, four detailed side views, and two black and white vertical views. These are played on the monitor along with the track section data
  • Picture caption: Having already input location data into the Zeta-Tech TieInspect, the sleeper inspector can use a custom-made handgrip to mark each sleeper as being in good, marginal or poor condition. This data is then downloaded into a computer with analytical software
  • Picture caption: A production plan detailed to the minute can be calculated with software developed by Hannover's Institute for Transport, Railway Construction & Operation
  • Picture caption: Plasser & Theurer's Dynamic Tamping Express 09-4X tamps four sleepers at once, and includes dynamic stabilisation
  • Picture caption: The latest version of Desec's Turnout Replacement Machine can replace a 40m long, 36 tonne turnout
  • Picture caption: Three shaker boxes (screens) increase the capacity of Plasser & Theurer's RM800 Super3S, 1 500 m3/h ballast cleaner
  • Picture caption: Speno International's RR16 MS-2 switch grinder includes the latest trolley-mounted measurement systems
  • Picture caption: The Robel Mobile Maintenance Unit enables track maintenance personnel to work in a safe, well-illuminated environment protected from the weather
  • Picture caption: Plasser & Theurer's Unimat 09-32 4S 475 4S continuous action tamper is designed to surface track and turnouts. The machine's three-point lifting system can handle concrete turnout bearers