Why are The New DLC Packages Much Larger Than The Old Ones?

With the update to Trainz 12 in SP1, some keen eyes users may have noticed the difference in the size of DLC packages. This is not due to the change in format; if the same assets are packed in both methods, the output is the same size. However, the new packages contain significantly more content, for the following reasons:

• Pack authors have been busy making extra content. You may notice that some of the packs contain significantly more content than they did previously. For example, check out the number of locos, carriages and wagons included with the SnC route.
• Content creators have been updating and fixing their assets. In some cases, these can be much more detailed (and therefore larger) than before. This might be from the pack authors, or it might be DLS sourced assets that the pack depends on.
• All packs have been updated to contain the latest versions of every required asset available at the time of packaging. No extra downloads are required, regardless of what is currently installed on the target machine. Some of the DLC Packs previously did not contain every asset required, and assumed a certain set of built-in content would be present. This caused problems between different Trainz versions (e.g. TS2010 and TS12), which we’re aiming to avoid in the future.
• Even for packs that did contain all the dependencies (e.g. the route packs that were previously capable of running stand-alone), the built-in assets are now sourced from the current version, not from TS2009 as they have been previously. In particular, trees have undergone a revolution between then and now - and are far more detailed, containing much more texture than they did previously, and are much larger on disk than they were back then.

All of these factors contribute to the overall larger file sizes for downloads compared to ones that have been shipped previously.