I am curious how this works with the EB in spk. Does the westbound train normally terminate in Spokane and join up with the EB train cars to form an eastbound train, or does the WB go all the way to Seattle.
Like tonight, the WB is 8 hrs late. Would this normally go all the way to sea but instead sits in Spokane all night. ( well day by the time it will get there).
I guess I'm confused that they have engines to get the cars to Spokane, so why do they not just send the east cars east and WB cars west.
Not totally clear what you are asking.
What usually happens if both east- and west- bound are near on-time at Spokane is -
There are two eastbound trains, one from SEA with two engines and 6 cars scheduled arrival 12:45A , one from PDX with one engine and 4 cars scheduled arrival 1213A.
The train from Portland has its engine cut off, the cars are coupled to the back of the section coming from Seattle, the EB now has 2 engines pulling 10 cars for the rest of its run to Chicago.
The single westbound arrives a bit later - scheduled at 01:40A , the tail 4 cars are cut off and go to PDX behind the recently arrived engine. The front part continues to Seattle with 2 engines.
When, (not if), the westbound is so late into Spokane that there's no way to get the two sections to SEA and/or PDX in time to turn them and keep within a few hours of schedule,
then the whole rig stops in Spokane, gets cleaned and turned,
and all the Seattle and Portland passengers are "bustituted" both east and west, to and from SEA and PDX.
There's not enough cars and engines in SEA or PDX to make up either eastbound train without the arriving westbound trains, so it's all buses to-from Spokane, whenever the westbound is really late.
The several times I've been on the Builder in either direction I've watched the switching, with several variations depending on lateness of any of the trains that split-merge there in the wee hours (Sleepless in Spokane is me). Never seen them turn the train there (not likely to either, cause would either be quickly herded onto bus westbound or arrived on bus with train already there when going eastbound)
Diverging - Spokane has plenty of switching space, and freight engines that Amtrak occasionnaly borrows.