Not surprisingly, I learned quite a bit about train orders from my trial-by-fire at the San Diego Model Railroad Museum last weekend.
Number one: OS's ("on sheet") where the operator warns the dispatcher when a train leaves a station gives the dispatcher some very important information so he knows when a track is occupied. On La Mesa, the dispatcher is "hungry" for any information like that, so it's ok to barge into the middle of an existing conversation on the phone to warn the dispatcher of a train's location. I barged in.
Number two: I'd assumed that train orders were addressed to all trains mentioned so the crew knew what other crews knew about the order. Wrong; I learned after my first set of orders that the dispatcher would warn the operator who was supposed to receive each set of orders, and I'd record only the names of the train receiving the orders at my station.
Number three: Most model railroads have a tiny amount of track between towns, but the La Mesa Club can have fifty or a hundred feet of track between stations. As a result, it's possible to reproduce one aspect of a train order operator - warning the dispatcher about a train approaching. I'd call out "Woodford coming west" on the phone when I saw a train approaching in the distance, and the dispatcher would tell me who it was, and if there were no more orders he intended for that train, warn me "No more", and I'd clear the train order signal and let the train go past. Several times, I couldn't barge into a conversation fast enough to warn the dispatcher; the layout rules said that if I couldn't reach the dispatcher, I'd have to let the train stop, then I'd have to create a clearance card indicating "no orders" and let the train through on the assumption the dispatcher had no more plans.
Number four: I almost freaked when I realized I still had an order for the second section of train 806 that was supposed to meet Extra 4230. Did I forget to give out the order? I later figured out that Extra 4230 left its siding before the second section arrived. Hopefully 2-806 was watching train numbers as it climbed out of Bakersfield and realized the train it was already waiting for had high-tailed it downhill ahead of its orders.