Late Autumn through Mid-Winter of 338 (Year 87)
For years, traffic has flowed through the underground trade network without a hitch. Wagons have been allowed occasionally, though if the humans were granted access for their wagons for a season, dwarven wagons were barred that same year to prevent traffic jams. This year, while the humans were packing up, the dwarven caravan was nowhere in sight.
Thinking that perhaps the earlier fighting with goblins had caused dwarven merchants to avoid the area, the human wagons were released. The dwarven caravan arrived soon after, causing a massive pile-up in the main northern tunnel.
The tunnel was expanded to no avail. The draft animals refused to budge, even when a troll prisoner was released nearby to frighten them into moving. Finally, several of the wagons broke down in the chaos and the merchants were able to squeeze by each other, though harsh words were shared between the humans and dwarves.