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Can you hear me?

Electrically powered maintenance vehicles allow noise reductions of more than 20 dBA.

Plasser & Theurer has worked on comprehensive measures to reduce the noise emitted by track construction and maintenance machines for many years. Design features on the machines reduce the noise created by both the machines and the construction works. With the integration of new drive technologies, such as the hybrid drive systems for track maintenance machines, Plasser & Theurer has broken new ground. The latest comparative measurements prove that the machines from the E³ series allow for noise reductions.

New drive concepts for soundless works

The E³ hybrid drive concept allows the machine to be powered either via a diesel engine or via an electric motor using the electrical energy of the contact wire. It reduces pollutant emissions, lowers the noise emitted by the machines and enables fossil fuel savings. 

In addition, noise protection measures reduce the noise emitted at the work units: the stabilising units are shielded laterally. Both the hopper unit and sweeper unit of the BDS 2000 E³ ballast management system are fitted with sound protection. These measures enable the machines to be operated in urban areas and during the night.

With our HTW 100 E³ hybrid tower car for works on the overhead line, we have taken things one step further. As the overhead line is not carrying electricity when such machines are used, we equipped the HTW 100 E³ with the latest battery technology. 

The perception of track maintenance works changes considerably: -20 dBA.

The human ear can perceive changes of 1 dB in volume under certain circumstances. Changes of around 10 dB in the noise level correspond to a doubling or halving of the subjectively perceived volume.


Current studies on noise reduction

Two fields of application of the machines with hybrid technology were tested with regard to the noise emitted during operation: Comparative measurements (Unimat 09-4x4/4S E³) and sound measurements in a tunnel (HTW 100 E³). In both cases, the noise reduction was confirmed.   

HTW 100 E³ reduces noise by more than 20 dBA

Compared to catenary renewal and installation machines with conventional drives, the HTW 100 E³ reduces the noise emitted during works on the overhead line system by more than 20 dBA. Sometimes, staff talking on the work platforms is the loudest noise coming from the machine. Even when the machine travels from one assembly point to the next, the HTW barely creates noise. Compared to other machines with diesel drive, the E³ electric drive system reduces noise emissions by more than 10 dBA.    

In working mode, the battery-powered HTW 100 E³ never exceeds 80 dBA, which is the exposure limit value requiring the use of hearing protection. Even when starting, the HTW emits around 15 dBA less noise than the diesel-powered machines from the MTW series.

Sound measurements of the UNIMAT 09-4x4/4S E³

The Unimat 09-4x4/4S E³ universal tamping machine uses the electrical energy not only for electrical traction during transfer travel, but also to power the tamping unit electrically for the first time. The crucial working parameters remain unchanged. If there is no overhead line available for current collection, a diesel-electric generator is used. This takes the classical tamping machine to a new level. 

The noise emitted by the electrically powered tamping unit is reduced by more than 20 dBA. This is a massive noise reduction, compared to units with fully hydraulically powered units. The noise created in idle mode is around 62 dBA, which is equal to the noise level of a normal conversation in the office.

During operation, the tamping machine’s drive car generates more than 13 dBA less noise than the drive car of a diesel-hydraulic machine. The all-electric E³ drive offers an ergonomically designed working environment, placing particular attention on staff protection.   

A long version of this article was published in: „Der Nahverkehr“, issue 5-2018

1,000,000 tamping cycles: endurance test for the E³ tamping unit

The work units are the core components of Plasser & Theurer machines. They determine not only the function of the machine but also its productivity and cost-efficiency. Before it is put into operation for the first time, a newly developed work unit must prove its efficiency and performance during stability tests and stress tests.

Our all-electric tamping unit was thoroughly tested. On a specially developed test rig, housed in a standard container, the work unit was put to the endurance test for four months. In total, 1,000,000 tamping cycles were carried out under simulated tine pressure (counterpressure of the ballast). This corresponds to around 20,000 tamping cycles per day or 250,000 tamping cycles per month. During peak testing, the work unit was operated for 14 hours a day. However, the end of the unit’s service life is not even in sight.

All major parameters were measured and particular attention was given to the temperature of the bearings. Once the test had been completed, the unit was taken apart and thoroughly inspected and analysed. The results are particularly promising for regular operation: They make it possible to further optimise the quality for the operation on track and provide important information for the production.