A con­sidera­ble poten­ti­al for more sus­taina­bi­li­ty in rail freight trans­port lies in noise aba­te­ment. Noise must be fur­ther redu­ced so that an increase in rail freight trans­port can be rea­li­sed wit­hout signi­fi­cant increa­ses in noise. This will then bene­fit the envi­ron­ment and the popu­la­ti­on. The spea­k­ers at the Noise Rese­arch Forum 2021 explai­ned which con­cepts and mea­su­res are curr­ent­ly being exami­ned and are promising.

At the Noise Rese­arch Forum 2021, the focus was on an essen­ti­al aspect of future-proof rail freight trans­port: auto­ma­ti­on. For rail to beco­me more attrac­ti­ve for freight trans­port, it must beco­me more effi­ci­ent and sus­tainable. One exam­p­le of this is the digi­tal auto­ma­tic cou­pler (DAK). It repres­ents a major mile­stone in auto­ma­ti­on and allows for a con­sidera­ble increase in effi­ci­en­cy in Euro­pean rail freight trans­port. If rail freight trans­port beco­mes more cost-effec­ti­ve, the share of rail in the total volu­me of traf­fic can increase, which favours CO2 reduction.

The manage­ment of infra­struc­tu­re and traf­fic must also be incre­asing­ly auto­ma­ted and digi­ta­li­sed. Real-time infor­ma­ti­on for cus­to­mers on the trans­port or safe ope­ra­ti­on of the wagons used and the cor­rect loa­ding as well as semi-auto­no­mous ope­ra­ti­on of the sidings streng­then rail freight trans­port. Start-up finan­cing would faci­li­ta­te the digi­tal trans­for­ma­ti­on, while at the same time sub­si­dies could be reduced.

The VAP makes a signi­fi­cant con­tri­bu­ti­on to streng­thening the inno­va­ti­ve strength and the will to trans­form of its mem­bers. Only in this way can rail freight trans­port beco­me more attrac­ti­ve and deve­lop into a valid alter­na­ti­ve to the road. To this end, the VAP sup­ports its mem­bers in the imple­men­ta­ti­on of auto­ma­ti­on in Switz­er­land, always in coor­di­na­ti­on with deve­lo­p­ments and requi­re­ments in Europe.

Detailed information from the Railway Noise Research Forum 2021

Rudolf Sper­lich, Vice-Direc­tor of the Fede­ral Office of Trans­port (FOT), wel­co­med the par­ti­ci­pan­ts and loo­ked back on the deve­lo­p­ment of noise reme­dia­ti­on to clas­si­fy the forum. He explai­ned Switz­er­lan­d’s pio­nee­ring role in Euro­pe and noted that the pro­gram­me had been imple­men­ted very suc­cessful­ly in terms of costs and dead­lines. Howe­ver, becau­se the effect fell just short of the sta­tu­to­ry reme­dia­ti­on tar­get, the par­lia­ment unani­mously adopted addi­tio­nal mea­su­res in 2013. Inno­va­ti­on assis­tance and depart­ment­al rese­arch are two of these sup­ple­men­ta­ry instru­ments that will expi­re in 2025. For this reason, a wealth of ideas, net­wor­king and the will to inno­va­te are once again cal­led for in order to help the new, inte­res­t­ing approa­ches to suc­cess or to broad application.

Paul Stef­fen, Vice Direc­tor at the Fede­ral Office for the Envi­ron­ment (FOEN), poin­ted out in his wel­co­me address the need for fur­ther inno­va­tions in the rail­ways. Inno­va­ti­on is still neces­sa­ry, not only for the health of resi­dents, but also to streng­then the envi­ron­men­tal advan­ta­ge of rail over road and thus to main­tain mar­ket share in freight transport.

Det­lef Schli­ckel­mann, repre­sen­ta­ti­ve of the VAP Swiss Rail Ship­pers Asso­cia­ti­on, explai­ned that the noise reme­dia­ti­on pro­ject ended in 2016 with the com­mis­sio­ning of the last 4,000 or so refur­bis­hed wagons. The indus­try had suc­cessful­ly orga­nis­ed the enti­re pro­cess of series engi­nee­ring, appr­oval, con­ver­si­on incl. mate­ri­al pool and finan­cing under the pro­ject manage­ment of the VAP. Schli­ckel­mann added that the digi­tal auto­ma­tic cou­pler (DAK) pro­ject would crea­te a great increase in effi­ci­en­cy in Euro­pean rail freight trans­port and that the VAP wan­ted to write a second suc­cess story for the pro­gress of rail freight trans­port with the rapid imple­men­ta­ti­on of the DAK project.

Rail­way noise rese­arch accor­ding to the Fede­ral Rail­way Noise Aba­te­ment Act (BGLE)
Fredy Fischer, Depu­ty Head of the Noise and NIR Divi­si­on at the FOEN, empha­sis­ed in his intro­duc­to­ry pre­sen­ta­ti­on how important it is for the rail­ways to beco­me even quie­ter. He cal­led on the indus­try repre­sen­ta­ti­ves to crea­te a com­mon visi­on of the quiet rail­way. If this requi­red rese­arch or deve­lo­p­ment, he said, the fede­ral govern­ment would be happy to sup­port projects.

5L demons­tra­tor train
Jens-Erik Gal­diks, head of fleet tech­no­lo­gy at SBB Cargo, used the “5L demons­tra­tor train” pro­ject to show that cur­rent tech­no­lo­gies can redu­ce the noise of freight wagons by a fur­ther 6 dB. Here, it is important to keep an eye on and con­sider the cost-bene­fit ratio. Other effects such as wear reduc­tion are also signi­fi­cant. These com­mer­cial effects do not neces­s­a­ri­ly accrue to the inves­tor. The­r­e­fo­re, a balan­ce of bene­fits bet­ween infra­struc­tu­re mana­gers, rail­way under­ta­kings and wagon kee­pers must be crea­ted. Jens-Erik Gal­diks fur­ther sta­ted that a fur­ther noise reduc­tion of freight wagons would be dis­pro­por­tio­na­te at pre­sent and that other mea­su­res such as opti­mi­sa­ti­on of loco­mo­ti­ves should be pursued.

Over­all opti­mi­sed inno­va­ti­ve freight wagon
Dr Hanno Schell, Head of Inno­va­ti­on at VTG Rail Euro­pe GmbH, spoke about the goal of desig­ning a quie­ter freight wagon. The first step was to redu­ce the weight by 800 kg and the sound from 83 dB(A) to 76 dB(A). VTG fur­ther deve­lo­ped the bogie of the type RC25NT-H‑D from the com­pa­ny ELH Eisen­bahn­lauf­wer­ke Halle GmbH & Co. KG fur­ther. It repla­ced the fric­tion dam­ping with hydrau­lic dam­ping. This enab­led it to save 200 kg per bogie in the cross beam at the draw­bar. VTG also instal­led Bona­trans wheel­sets with a noise-redu­cing BASF coa­ting. A wel­ded steel disc was used for the disc brake, which is 49 kg ligh­ter than con­ven­tio­nal cast discs; a fur­ther 13 kg could be saved on the disc brake cali­per. Various tests have alre­a­dy been car­ri­ed out in Switz­er­land with the quie­ter bogie. All in all, it would allow hig­her dri­ving speeds, take more weight and, thanks to the hydrau­lic dam­ping, have very good run­ning characteristics.

Com­po­si­te wheel­set
Pro­fes­sor Masoud Mota­val­li, head of the Struc­tu­ral Engi­nee­ring Depart­ment at the Swiss Fede­ral Labo­ra­to­ries for Mate­ri­als Test­ing and Rese­arch (Empa), spoke about the use of light­weight and high-strength fibre-rein­forced pla­s­tics to pro­du­ce a com­po­si­te wheel­set and a com­po­si­te bogie. A fea­si­bi­li­ty study show­ed that the desi­gned wheel­set was 40% ligh­ter than the con­ven­tio­nal metal ver­si­on. In addi­ti­on, a noise reduc­tion of 3 dB was achie­ved. The car­bon fibre-rein­forced pla­s­tics are cor­ro­si­on-resistant, have a very long ser­vice life and high fati­gue strength, but are much more expen­si­ve com­pared to clas­sic mate­ri­als. Masoud Mota­val­li the­r­e­fo­re pro­po­ses to design an enti­re bogie out of com­po­si­tes, becau­se this would make opti­mi­sed pri­cing more fea­si­ble. He is con­vin­ced that a mas­si­ve weight reduc­tion would be pos­si­ble and the self-dam­ping of the mate­ri­al would redu­ce the num­ber of dam­pers. In addi­ti­on, other inno­va­tions could be incor­po­ra­ted, for exam­p­le self-stee­ring, which would redu­ce the wear and tear on the tracks. All this would bring a signi­fi­cant noise reduc­tion com­pared to con­ven­tio­nal bogies.

Deve­lo­p­ment of a super­s­truc­tu­re simu­la­ti­on tool
In his pre­sen­ta­ti­on, Jean Marc Wun­der­li, Head of the Acoustics/Noise Reduc­tion Depart­ment at Empa, pre­sen­ted a nume­ri­cal model for the simu­la­ti­on of roll­over pro­ces­ses, which simu­la­tes the resul­ting cont­act forces, the struc­tu­ral vibra­ti­ons and final­ly the radia­ted air­bor­ne sound in three modu­les. Mr Wun­der­li empha­sis­ed that simu­la­ti­on tools that model­led the sound gene­ra­ti­on and radia­ti­on of the rol­ling noise of rail­ways in a phy­si­cal­ly cor­rect man­ner were a man­da­to­ry pre­re­qui­si­te for opti­mi­sa­ti­ons to the vehic­le and super­s­truc­tu­re. Due to the high com­ple­xi­ty of the sys­tem and the part­ly con­tra­dic­to­ry requi­re­ments (noise, vibra­ti­ons, wear, posi­tio­nal sta­bi­li­ty …), a trial-and-error approach was not expedient.

“Rail pads – less rol­ling noise and more pro­tec­tion
Hol­ger Frau­en­rath, pro­fes­sor at the Insti­tu­te of Mate­ri­als Sci­ence at the Ecole Poly­tech­ni­que Fédé­ra­le de Lau­sanne (EPFL), pre­sen­ted a pro­ject to deve­lop new types of rail pads. These should enable both bet­ter pro­tec­tion of the rail­way super­s­truc­tu­re and a noise reduc­tion of at least 1 dB (A) com­pared to con­ven­tio­nal rail pads. The mul­ti­di­sci­pli­na­ry pro­ject team brings tog­e­ther rese­ar­chers from EPFL, HEIG Yver­don and Empa from the fields of mate­ri­als sci­ence, nume­ri­cal simu­la­ti­on, vibroa­cou­stics, envi­ron­men­tal engi­neers and rail­way experts from SBB. Based on an expe­ri­men­tal model­ling chain ran­ging from the mate­ri­al pro­per­ties to the beha­viour of a rail pad as a com­po­nent to the sys­tem beha­viour in the track, new multi-mate­ri­al rail pads with a soft core with high dam­ping capa­ci­ty bet­ween 200 and 2’000 Hz are deve­lo­ped. These will be opti­mi­sed for a good balan­ce bet­ween mecha­ni­cal sta­bi­li­ty, noise reduc­tion and per­ma­nent way pro­tec­tion. Designs are curr­ent­ly being tes­ted to Euro­pean stan­dards and pre­pared for the final deve­lo­p­ment phase, which will invol­ve the pro­duc­tion of engi­nee­ring-scale pro­to­ty­pes for field tri­als in the track from March 2022. The new rail pads will be of inte­rest both for redu­ced noise pol­lu­ti­on in den­se­ly popu­la­ted count­ries and for rail­way ope­ra­tors, as they should redu­ce the costs of main­tai­ning the per­ma­nent way.

Opti­mi­sed con­cre­te slee­per, opti­mi­sed inter­me­dia­te layer
Dr Chris­ti­an Czol­be, Seni­or Engi­neer Acou­stics at PROSE AG, show­ed that noise along rail­way lines depends on both the rol­ling stock and the com­pon­ents in the track. For the infra­struc­tu­re, it the­r­e­fo­re makes sense to take mea­su­res that increase rail dam­ping and redu­ce rail noise. In a rese­arch pro­ject, PROSE deve­lo­ped acou­sti­cal­ly opti­mi­sed con­cre­te slee­pers tog­e­ther with Vigier Rail and exami­ned two pro­mi­sing pro­to­ty­pes in a test track. In ano­ther pro­ject, an incon­spi­cuous and bare­ly visi­ble com­po­nent bet­ween rail and slee­per was opti­mi­sed. Dr. Chris­ti­an Czol­be sta­ted that the deve­lo­ped Bate­gu inter­me­dia­te layer unites a long­stan­ding demand of the rail­way indus­try: it dam­pens the dyna­mic impact loads in the super­s­truc­tu­re and redu­ces noise at the same time. With a mea­su­red noise reduc­tion of up to 5 dB (A), it would be signi­fi­cant­ly quie­ter along the line, which resi­dents could per­cei­ve and con­firm imme­dia­te­ly after its instal­la­ti­on. It also pro­tects the track super­s­truc­tu­re and thus leads to a reduc­tion in life cycle costs – a win-win situa­ti­on for the rail­way indus­try and resi­dents. The new Bate­gu inter­me­dia­te layer has pas­sed all rele­vant stan­dard and field tests as well as the fati­gue strength tests and is now available for safe series use in the rail­way infrastructure.

Mea­su­re­ment of acou­stic rough­ness
Flo­ri­an Mauz, rese­arch asso­cia­te and doc­to­ral stu­dent at ETH Zurich, pre­sen­ted a deve­lo­p­ment approach for an opti­cal mea­su­ring device for mea­su­ring acou­stic rough­ness on rails. In the future, it should be pos­si­ble to mea­su­re the rough­ness from the moving train. By cle­ver­ly com­bi­ning seve­ral sen­sors, the mea­su­re­ment result could be opti­mi­sed. Flo­ri­an Mauz show­ed the test setup and the series of tests in a labo­ra­to­ry envi­ron­ment. Soon the approach would be tes­ted on a moving train and vali­da­ted for its accuracy.

The link to the Forum’s web­site is www.laermforschung-eisenbahn.ch.

Fur­ther infor­ma­ti­on on the depart­ment­al rail­way rese­arch and the award cri­te­ria can be found on the FOEN web­site (in ger­man, french or italian).