Marathon2Operation, a Shift2Rail project for radio communication and simulation of train dynamics for distributed power within long trains

Simulation of freight trains with up to three traction units in radio communication

“…Figure 6 is like figure 5 but the train performs the other manoeuvre listed before; moreover, it operates in G regime and in direction FW. For this manoeuvre, the DPS train is usually worse than the REF train and this is confirmed also by other results reported in [6]. The reason for this behaviour is the current implementation of DPS: when the radio link is lost, the electrodynamic force reduces automatically, and this causes a compressive wave (an example is given in figure 7), resulting in higher LCF.…”

“…Several results reported in this paper can be found also in M2O deliverables [6] and [7]; however, this paper adds further insights to those results, highlights and systematizes the main assumptions and conclusions of these deliverables. The paper is organized as follows: a) section 2 is dedicated to explain the features of the train and of the track on which the train is tested; b) section 3 reports the way used to determine the experimental train make up and the train operations simulated; c) section 4 shows the main results in terms of in-train forces and stopping distances, for different working conditions of DPS; d) section 5 reports the conclusions and the future work on the subject.…”

“…About the train manoeuvres, the emergency braking from 30 km/h after the train acceleration is used as manoeuvre since it provides high levels of in-train forces. This manoeuvre is simulated considering a radio communication between the TUs ( ) and assuming it is lost at the same time ( ) the emergency braking is commanded by the Driver: these conditions are the worst in agreement with the experience and the results reported in [6]. When the radio link is on, the command at the leading TU, because of DPS technology, is replicated by the remote TUs with a delay given by the technology implemented (4G, LTE radio protocol has been used in the tests): consider that for REF trains, the venting of brake pipe at the remote TU is not allowed, unless the pressure in brake pipe is 3.5 bar.…”

“…• Electrodynamic braking + First Application Step of braking (target pressure in brake pipe is 4.5 bar) followed by an emergency braking, when the speed is 30 km/h. In this scenario, the radio link is lost before the emergency braking is applied: for this combination of train operation and track (the train is around point DF of figure 1) this condition is the worst, according to simulations reported in [6]. Figure 5 reports the comparison of in-train forces between REF and DPS trains for different positions around point UD where the emergency braking is commanded, figure 1 (b), and for different variations of the technical parameters considered most influencing for the in-train forces, see [10]: the first row shows the cumulative frequency for REF trains on the left and the variability of LCF and LTF on the right (LTF are positive and LCF are negative, in this representation).…”

“…In this section, two train operations are considered (for the complete list of simulations needed to check the in-train forces of DPS trains against those of REF trains refer to [6]). Namely:…”