Hi Max,
you can also use portals (one that looks like gateway to heaven <kuid:30501:22006>, or other resembling entrance to tunnel <kuid:-3:10192>) to dump general goods as well as other commodities and use another portal to load trains. Unlike other industries, portal can produce and consume large quantity of general goods, how large I don’t know exactly, but I tested it successfully with 36 boxcars, each loaded with 9 boxes, which gives total of 324 boxes, 27% more than the factory you chose. In fact, I use portals extensively to load/unload long (by this I mean longer than 800 meters) or very heavy (pulling weight 3000 tonnes or more) trains and route these trains to big shunting yards, where the trains are broken into smaller consists to service local industries. Portals are very efficient when handling big loads – it takes about 7 minutes to unload 34 40’ containers in Industry Multiple Advanced <kuid:-19:10165>, which is fastest loading/unloading industry or you can send that many containers to a portal and have returned empty consist after only 1 minute.
But portals have their limits and disadvantages, as everything in Trainz and I wouldn’t be totally honest with you, if I haven’t mentioned the three I am aware off (perhaps there are many more I was lucky enough not to discover):
1/ Only default commodity can be loaded in portal, although any commodity can be unloaded in portal. For example, default commodity for TRS Flatcar <kuid:-3:10028> are Logs <kuid:-3:10001> and for MN MOW BoxCar 01 <kuid:523:133333> are General Goods <kuid:-3:10013>. To change default commodity you need to modify truck configuration file. You can find many articles how to do it on this very forum, but it is much easier to simply select correct truck type.
2/ If you use more than one consist of given truck type (e.g. flat cars), the trucks are likely to be re-numbered each time they leave a portal. For instance, if you have consist with trucks numbered 1 to 10 and sent it to a portal, it will re-appear (well, not always, see point 3) with the trucks numbered 11-20 and so on. If you have many consists with many trucks, numbers are likely to increase very quickly, although I never had enough stamina to run single session long enough to find out what happens when numbers hit the ceiling, will it cause an overflow or some other error. But if you have some logic programmed into your session that depends on fixed truck numbers, portals are likely to break this logic. Perhaps there are other properties prone to changes when trains travel via portals.
3/ When you save session while a train is in portal you probably won’t see this train again, when you load saved session. The driver, the loco and the precious cargo worth maybe hundreds of thousands of dollars are lost forever in computer void. This is by far the most severe side effect of adding portals to your map. The only countermeasure I know is to check number of the trains in the driver left-side panel before saving, but with many trains running, it is easy to make miscalculation or sometimes simply you have to shut down your computer without delay. I see that you use latest version of Trainz, so there is a chance this problem was fixed. If this is the case, I would like to know about it, before getting this version myself. But I doubt it, because no sensibly thinking company would dare to re-engineer their product completely and from most of the posts I read here I got the picture, this is rather “A New Era With Old Problems”.