**5.3 Intra-site logistics**

Similar to port operations, there may also be other loading sites that require intensive cooperation with the customer and the moving of wagons during loading operations. Typically, this may be the filling and unloading of tank wagons, where the loading site has a limited length and offers only unloading single or small groups of wagons simultaneously, or hopper wagons that need to be filled or emptied at a loading site. If these sites are highly frequented, they are often equipped with electric tractors or steel cables/ winches to move wagons during (un-)loading operations. But for smaller sites, this kind of infrastructure is too expensive. So, for small customers, the railway operator keeps his locomotive and staff busy supporting the loading operations, which is not very cost-efficient. The same applies for loading sites inside a plant, for example, a household appliances factory doing metal forming. Normally, these factories receive single wagons with coils of steel sheets, which must be positioned under a crane for unloading. Currently, at such sites, the only option is to ask the railway operator to move the wagons or have their own shunting tractor. This is especially costly for small factories that do not receive high volumes of wagons. The Wagon 4.0 class 5 overcomes these challenges as it features a shunting drive system. Without needing additional assets, the customer may now move the wagons himself on his premises by using the shunting drive.

### **5.4 Power boost by distributed power**

Depending on the velocity range of operation and the local legislation, the shunting drive may remain activated in certain velocity ranges during mainline operation. Using cooperative control, that is, the wagons apply tractive power if their neighbouring wagons apply it, the train may be able to help the locomotives in certain situations, for example, when starting or on steep uphill grades.

#### **Figure 10.**

*Port operation stages.*

This reduces longitudinal forces in the train consist and makes higher commercial speeds possible.

**Figure 11** shows a simulation of a train set up with 30 container cars type Sgjs, each of them loaded with three 20'-containers. The total train mass is in the range of 1100 t. As a loco, a DB class 145 (mass 82 t) is assumed, delivering 250 kN of tractive effort and a power of 4.2 MW.

W40 class 5 is equipped with a traction system. In this way, the wagons may operate like multiple-unit vehicles and support the locomotive during acceleration.

When using the tractive capabilities of the W40 for a short term during the acceleration of the train, the tractive effort of the whole composition will be 880 kN, signifying an increase by a factor of 3.5.

The short-term power of the system will only increase slightly by 10%. That means, as shown in **Figure 11**, that use of the tractive capabilities of the W40 makes only sense for speeds below 20 km/h.

This velocity range, however, is the range that is important for freight traffic. Normally, turnouts in freight yards are designed for branch speeds of 40 km/h due to cost reasons. Consequently, the most important task is accelerating up to 40 km/h as fast as possible to reduce the occupation and locking times of train path elements in the interlocking system. As an initial estimate, the acceleration will take approximately 1 minute less with W40 traction applied.

On heavily used mainlines, headways are normally in the order of four minutes, so saving one minute during the acceleration of a freight train may significantly increase capacity in congested nodes.

#### **Figure 11.**

*Traction curves of individual W40 ( F*W 40 *), a locomotive ( F*Loco *), a train of 30 W40 ( F*Train *) as well as the total tractive effort of the train setup.*

#### **5.5 ep-light brake**

Thanks to the continuous power supply of the W40 and the intra-train network capability, it is possible to extend the brake system of the wagon by a valve to command an indirect electro-pneumatic brake application locally.

This is achieved by locally venting the brake pipe to the atmosphere. The benefit of locally commanded brake application (ep-apply) is a faster propagation of the brake request through the brake pipe, which leads to three effects:

**Figure 12.** *Traction power boost by distributed power.*


The reduction of buff forces may lead to increased train masses being braked in the P-regime, which in turn also increases maximum velocities. In terms of industry 4.0, the ep-assisted brake can be considered a collaborative function, as no master is required for this functionality. Instead, the wagons support each other in braking the train, with the most sensible way to react to the neighbouring wagon's braking being to support the process.

Depending on the treatment of the improved functionality with respect to operations (i.e., braked weight, train length and masses), such a function does not require particularly high equipment safety levels, since failures in individual wagons do not impede the overall safety of braking at the whole train level due to the continuous brake pipe.
