A notable break-through were the notion that it is now possible to construct light- weight (single hull) vessels for traffic in icy conditions. That is from the background that it's expensive to run heavy year-round vessels during summertime when resistance is less but the vessels still heavy. This has been a major difficulty in making long-distance water-based public transportation a reality in the sweet water lake of Mälaren in western Stockholm were ice is especially common.
I provided my knowledge from studies in urban planning and public transport planning to the many interesting discussions that took place.