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Cargo center with traffic sponge and pads for two cargo stations

I slightly modified the cargo sponge and laid out roads to two cargo stations. By upgrading all the legs of the sponge to 2-lane roads and splitting it off to two destinations at the end it forces the AI to use both lanes, thereby doubling the capacity of the sponge.It's probably possible to do the same with a traffic manager. But this gives vanilla players some degree of control over the traffic. A lot will also probably depend on where you route traffic when it leaves the stations.

The screenshot is just a demo to show that everything fits together. The exact arrangement will depend on your map and how you want to route things. I was also limited by the tiny space given in the asset editor.

The stations in the screenshot are the vanilla station. I tried it with a souped-up station from the workshop and had problems with interference and "slope too steep". So keep that in mind. If you want to use a station with extra tracks or sub-buildings you'll be better off getting the sponge and starting from scratch since the road layout here would have to be modified to fit.

I can't remember which sponge I used. I don't know who created it, but these two designs are rather similar:
https://steamproxy.net/sharedfiles/filedetails/?id=502593656
https://steamproxy.net/sharedfiles/filedetails/?id=410836766

You can't really see much of it in the picture, but I also used this at the end of each rail segment. It's a handy way of letting trains switch tracks, reverse directions, or even just get out of the way:
https://steamproxy.net/sharedfiles/filedetails/?id=480770704

The only other non-vanilla asset in this screenshot is the track that has had the catenaries removed. I couldn't remove it from the stations, but I did upgrade the rest of the track. It's a cleaner look and saves a bit of rendering effort:
https://steamproxy.net/sharedfiles/filedetails/?id=1410663208