Although the war eventually brought heavy commerce, the start of the war caused
a big drop in late 1914 and in 1915, just when America coulda'. woulda' been gearing up.
Of course, as is usual, Woodrow won the 1916 election on 'He kept us out of war' and then turned around, declared war in a very poor state of preparation, and instituted draconian measures against dissent
There were some benefits to USRA
USRA locomotive designs were good- so good that parts were incorporated in later loco orders.
For examples, examine the SP later P classes and the SOU Ps4- Heavy Pacific boilers on Light Pacific running gear. in effect.
But the USRA locos arrived too late-mostly in time for the 1921-22 slump.
Lemme see- do you run the newest and store some of the older, requiring double spares, or do you store the odd new ones use standard spares?
Some railroads that received few of a kind sold them off, such as a group of WP Mikes.
SOU for one bought fleets of certain USRA designs

Kruttschnitt was the leader of the opposition- but he could not force RRs to cooperate.
Quite likely if the RRs did cooperate, the ICC would have screwed it up very badly by negativism and a snail's pace. Oh, and by using raw materials, spares and its own foundries and shops, SP avoided USRA locomotives in favor of SP standard types. For cars, SP got USRA SS boxcars, and built mostly wood 40 ton cars in SP and PE shops [ and some 50 ton flats].

ONe can argue that the necessary streamlining of facilities etc. could have been much better handled by an ODT-like small group [see below] that could tell the ICC to siddown and shuddup rather than seizure.

Fiasco 1 USRA directed so much traffic to the Colorado Midland that it was overwhelmed.
Duh, did USRA consider where the motive power was to come from?. So CM was embargoed- no traffic, no income, bancruptcy, and the biggest abandonment to that time and until O&W folded after WW2. But the Brotherhoods struck after the embargo

USRA, under a change of director wanted to hold onto the RRs for 'more' years to experiment and diddle. THe RRs united in opposition, led by Kruttschnitt.

Much of the fiasco can be attributed to ocean shipping problems on the east coast- RR traffic simply was blocked by failure to unload and get the cargoes onto ships, and empties back to loading. That affected coal shipments to some degree and a coal shortage developed. ALthough many wood and concrete ships were built to save steel, only a handful saw actual use- too late for the war due to poor management. MOst of the wood ships were burned to the waterline in Chesapeake Bay

Perhaps the biggest fiasca were the acts that returned control to the RR owners. These set and restricted RR rates to very low levels [and the ICC kept them there for decades], but the acts increased RR worker wages greatly

For WW2, there was preparation, if very insufficient in hindsight- politics and that
"conflict isn't nice, so if we are nice nobody will bother us but just be nice right back", until they kick our teeth in. "Peace in our time" just barely gave Britain time to perfect the Hurricane, the Spitfire and Radar, but not time to build a nightfighter. How did that work out for the Czechs, Poles, etc?
The 1940 draft and early aircraft orders were a couple steps. Plus the RRs, were lifted out of the 1938 slump by foreign orders in 1939. RRs were able to order rolling stock.
WW2 brought the ODT and WPB. The ODT set priorities - Premium freight services were stopped, overnight Pullman service was banned for runs under 450 miles [ or so]
In the east trucks took over from tank cars for 'short' deliveries and all [Midwest and Eastern] tankcars were drafted for oil service from OK-TX until pipelines were built to shorten the run to East-West. Oil trains were run as units to/from the refineries.
Coal from Tidewater to New York and New England was similarly banned from ships.
Some folks say Virginian 120 ton coal gons were seen on PRR's Horseshoe.
WPB set materials priorities, such as who could order locomotives. SP could buy GS-1s as GS-6s, diverting a handful to WP. Car designs that used less steel and more wood were prepared and built in thousands.

Not too bad, except that the RRs were worn out, and while industry was being returned to civilian production [say automobiles], the RRs had to continue to move service men as before, while folks took their money to Kingman AZ to pick out a nice C-47 that could be easily and quickly converted into a DC-3 for a new small airline.

Well you wanted an essay, Ese