Because the Amfleet II's were delivered in 1981 to 1983 and thus the cars will be 30 years old soon. The Amfleet Is are older, delivered in 1975 to 1978. There is a long lead time to replace the cars, so you have to start the process well before they have to be replaced. Amtrak can't go to the train car dealership and buy coach cars from inventory. The Viewliner 2 order, after, what?, a year or more to go through the RFP, bid review, and contract award negotiation process, was placed last summer with the first cars to be delivered in the fall of 2012. The new Viewliners won't be showing up in the fleet until 2013 until the initial units go through testing and won't all be delivered until 2015 at the earliest.I've said it before and I'll say it again... what is wrong with the Amfleet II's that they need to be replaced? I've ridden on them plenty of times and they seem just fine...
The Amfleet I and II fleet is in pretty good shape after the recent surge of overhauls and restorations from storage. But if you are the Amtrak fleet manager, you have to look 5, 10, 15 years out at what will need to be replaced by then. Of course, the uncertain funding picture from year to year makes it very difficult to establish a stable budget for fleet replacement. Hopefully, when the first big single level coach order is placed and deliveries start, Amtrak will keep the Amfleet Is and IIs around for a while to expand their capacity to meet what I would expect will be consistent growth in ridership.