SIEMENS is predicting a step-change in high-speed rail operation and travel with its new Velaro Novo train which is expected to cost 20% less than its existing Velaro trains, achieve a 30% reduction in energy consumption at 300km/h compared with Velaro, and a 15% reduction in train weight. Siemens also expects a 30% saving on maintenance costs and a 10% increase in available space.
These figures will be music to the ears of operators as they will translate into much lower operating costs while it will be possible to carry more passengers per train, so the cost per passenger will be lower than today.
Velaro Novo will build on the success of Siemens’ original Velaro high-speed train which includes the ICE 3 fleet operated by German Rail (DB). The first train entered service with DB in time for Expo 2000. Siemens has since sold more than 1000 Velaro trains to DB, Renfe, Spain, Eurostar, China Railways Corporation, Turkish State Railways (TCDD) and its 1520mm-gauge Velaro RUS version to Russian Railways (RZD). Velaro is used in seven European countries and the fleets operate a combined total of more than 1 million km per day.
Velaro reached 403km/h during trials without modifications and pioneered commercial 350km/h operation in Spain. It also represented a milestone in high-speed train design for Siemens as it marked a move away from separate power cars and trailer coaches, favoured by European train builders, to distributed traction, which has been a feature of Japanese high-speed trains since the opening of the first Shinkansen line in 1964.
While subsequent builds of Velaro have benefitted from advances in technology, its overall design and concept dates from the 1990s, and with pressure on operators to reduce costs, pressure on prices through increased competition and potentially from China, and new projects on the horizon such as HS2 in Britain, and schemes in North America and Asia, Siemens felt it was time for a rethink.
“In 2013, when we started to think about the next step in high-speed train design, we were just selling Velaro to Eurostar,” Mr Michael Kopp, high-speed platform programme director with Siemens, told IRJ. “We analysed the existing and upcoming market with new lines in California or the Kuala Lumpur - Singapore high-speed project in prospect, while the Chinese were coming up with competitive prices. Our analysis showed that even though Velaro is a good product, it is still a European design and there are more optimum possibilities. So we decided to develop the next generation of high-speed train to maintain our competitiveness.
“The objective was to lower the cost of the train itself, reduce energy consumption, the weight of the train and its maintenance costs, while at the same time optimising the passenger area to provide more comfort or more seats, and achieve a low life-cycle cost. We want to develop the most cost-efficient high-speed train, and up to now we have reduced the investment cost of the train by 20%.”
Kopp says the Velaro Novo project team was not under any pressure to develop the new train quickly as Velaro was still selling well. “We didn’t have a project timescale so we could take five years to go through all the different systems, and go through things twice if necessary, to make the design better,” Kopp explains. “We looked at the technologies and innovations that were available to reduce weight, cost, energy consumption and maintenance, but we didn’t adopt something just because it was an innovation. Everyone working on Velaro Novo wanted to make the train successful, and our discussions were always about solutions, rather than solving problems.
“Today, all the key systems have been developed and designed, and there are only small challenges to solve. The Velaro Novo test car has the same body, bogies and windows that will be on the series-production train including the drive system and auxiliary converters.
“The train interior is less well defined,” Kopp admits. “We have some standard components we can use, but the final design will depend on the customer’s needs.”
Trials with the test car started in Germany in April and endurance testing will continue until the end of 2019, while component testing is running in parallel. DB Systemtechnik is supporting Siemens with the test programme and has provided two trains for the Velaro Novo test car to operate with:
- a locomotive-hauled train with two measurement cars for test running up to 200km/h, and
- DB Systemtechnik’s ICE-S high-speed train comprising two power cars and two measurement cars with the Velaro Novo car located in the centre of the train for trials up to 330km/h, which is the maximum allowed by DB.
The ICE-S power cars can run at speeds of up to 400km/h. The Velaro Novo test car has already reached 331km/h with ICE-S and Kopp says the measurements from the tests so far “are in line with our simulations.”
While Kopp acknowledges there is still a way to go, Siemens will be in a position to supply the first train in 2021, with a view to entry into service in 2023.
Scalable traction system
Velaro Novo will have what Siemens describes as a scalable traction system for maximum speeds ranging from 250km/h to 360km/h with power outputs of between 4.7MW and 8MW. “Basically, the train is still an EMU, but it will have three powered cars and four non-powered cars for 360km/h operation, but with a lower maximum speed we can reduce the number of driven bogies, so that if a maximum of only 280km/h is required by the customer then we will only need two powered cars,” Kopp explains. “However, we always use the same basic components in the traction system.”
Synchronous permanent magnet motors will be used on Velaro Novo rather than the asynchronous motors employed in the current Velaro. “We have already tested permanent magnet motors on Velaro RUS, running for one year in commercial service,” Kopp says. “The challenge was not the performance of the motor itself, but what happens in degraded mode especially regarding fire safety - we have now found solutions to this problem.”
Permanent magnet motors are not only smaller than the previous generation of asynchronous traction motors, they also offer greater power efficiency. This means 12 permanent magnet motors can achieve an output 8MW on a 200m-long train, compared with the 16 asynchronous traction motors which are needed to power a Velaro train of the same length (Table 1).
There is another benefit from using permanent magnet motors as they allow pure electric braking under normal braking conditions, and on Velaro Novo this will be sufficient even with a maximum speed of 360km/h. The numbers relating to the use of permanent magnet bogies are impressive: a 10% increase in traction power, a 70% increase in braking power, and a 5% energy efficiency improvement.
Pure electric braking will maximise electricity regeneration thereby reducing energy consumption. Braking resistors will be available if the catenary is unable to recoup the electricity. “We will still have axle disc brakes on the trailer bogies and additionally tread brakes on the powered and trailer bogies, but only for emergency braking,” Kopp explains.
Permanent magnet motors are expected to contribute to the reduction in energy consumption, which Siemens estimates will cut carbon emissions by 1375 tonnes per train per annum, while the new traction and braking system should cut maintenance costs.
Velaro Novo will have a new design of aerodynamic pantograph, which is narrower than the pantographs fitted to Velaro. This is so that the pantograph can fit within a housing to improve the aerodynamics of the train. The pantograph will not have separate insulators as the frame and underarm isolate the voltage. The high-voltage roof equipment is completely isolated so that it can be covered to achieve a completely enclosed roof.
Siemens estimates the streamlined roof will cut energy consumption on Velaro Novo by 10%. This is also quite an achievement considering ICE 3 and Velaro already offered optimised aerodynamics, with shrouding around roof-mounted equipment, the bogies, and inter-car gangways designed to reduce drag and cut energy consumption. Velaro Novo will take this a step further with fully enclosed bogies, housed roof equipment, and inter-car gangways which are flush with the body shell. The fully-enclosed bogies will achieve another 15% energy saving and cut noise emissions.
The train will feature inside-frame bogies with the bearings on the inside of the wheels to enable them to be enclosed. “The bogie is lighter because the dimensions are smaller than on Velaro,” Kopp explains. This creates a challenge because there is less space available for the traction system, but Siemens was able to solve the problem by using the compact permanent magnet motors.
“Inside frame trailer bogies have existed for about 25 years and our Thameslink Desiro City EMUs have inside frame motor and trailer bogies, but this is the first time we have used them on a high-speed train,” Kopp says. The Thameslink Desiro City inside-frame bogie design was combined with experience gained from the bogies used on Velaro and further modified to develop the Velaro Novo bogies. Siemens says the inbound bearings will substantially reduce the weight of both the motor and trailer bogies compared with Velaro and the resulting lower unsprung mass will ensure a smoother ride and less wear.
“We don’t develop innovations just for high-speed trains,” Kopp says. “We are always trying to see what we have which can be applied elsewhere. The auxiliary converters on Velaro Novo came from our experience with metro trains, and the inter-car fire separation system came from regional trains. On Velaro Novo we are using the windows which were developed for regional trains to allow mobile phone signals to pass through them which obviates the need for repeaters.”
Kopp points out that the overall energy saving of 30% relates to operation at 300km/h, but says it will be even better at 360km/h. “The faster you go, the greater the influence of aerodynamics is on the reduction in energy consumption,” he observes.
Velaro Novo should be kinder to the track than Velaro as it will weigh 15% less. “Weight drives wear on the infrastructure,” Kopp says. “In Britain, Network Rail (NR) has variable access charges to incentivise the use of lighter trains which do less damage to the track. The inner-bearing bogies on the Thameslink Desiro City trains are designed to meet the NR specifications.”
Velaro Novo will adopt what Siemens describes as the “empty tube” concept for the passenger coaches as there will not be any permanent installations or electrical equipment inside the vehicles or under the seats to reduce the space available for passengers. This means the trains can be fitted out to the customer’s exact requirements and the seating layout can be changed easily if required.
Velaro Novo also features longer vehicles than its predecessor. Driving cars will be 29.285m long while the intermediate coaches will be 28.75m long with a total train length of 202.32m. While a longer car body necessitates a reduction in overall width to keep within the loading gauge through curves, Siemens has seemingly achieved the impossible: increasing the aisle width by 11mm without reducing the seat width even though the Velaro Novo coaches will be 2880mm wide compared with 2942mm on Velaro. “We are using a new type of aluminium profile for the Velaro Novo carbody which reduces the thickness of the skin from 4mm on Velaro to 2mm,” Kopp explains. This not only increases the internal width but also contributes to weight reduction. Siemens will also offer a wide-body variant to railways with a more generous loading gauge to allow 2+3 seating in second class.
The carbodies for Velaro Novo are manufactured using friction stir welding. “Not only does this require less energy when you weld the plates together, there is less reworking and friction stir welding produces a better quality weld,” Kopp explains. “We use composite plates for the roof section and new materials inside the train.”
Finally, considerable thought has been given to maintaining Velaro Novo. Siemens says the train will have measurement and sensor technology to enable continuous collection of operating data for analysis and to provide precise information about the train’s performance to facilitate predictive, condition-based maintenance. In addition, the electric braking system is almost maintenance free.
Velaro Novo will clearly set new standards for high-speed operation, but the last word should go to the CEO of Siemens Mobility, Ms Sabrina Soussan: “Velaro Novo is our answer to global demands in high-speed transport. The new train writes a new chapter in the Velaro’s success story and enables operators to offer improved passenger comfort and economy over the train’s entire lifecycle.”