Was there an assassin on Grant's train?

[Wild Bill]

I am willing to go along with Fazio's assertion that John Surratt gave the plan to use Harney to Booth, and possibly revealed a follow-up if Harney failed to get into DC, but the rest of it I dunno.

Booth and his men could get into the White House basement and had done so several times. So Harney's plan would work, providing nothing happened to thwart it. But Harney was intercepted, probably accidentally, by elements of the 8th Illinois Cavalry at Burke's Station outside DC and the mule carrying 50 lbs of black powder in two kegs got roughed up in the fight and half of the load was scattered along the road. The existence of such a cargo would have gone around the military and civilian population of DC in a flash and become the talk of the town. Booth surely would have heard of the incident. I tend to agree with THG, Come Retribution, that there is nothing more dangerous than an agent behind enemy lines wondering what to do if the plan is falling apart and no one speaking to him from command.

Telegraphy was high tech for the 1860s and not many knew its mysteries unless one had worked on the railroads before the war. I know we had to learn Morse Code when I was a Boy Scout (in the days before the controversy over gay scoutmasters--ours was a defense attorney, and believe me, we needed him!), but I can testify that sending and receiving a message at full speed is no easy task to master. There could have been a telegrapher with Mosby's men, but I bet not. This was a flying column, not a headquarters unit--one with a telegrapher or a portable handset, a box to send a message and a 10-12 foot pole to access a line. A real telegraphic unit usually travelled by wagon in the Civil War, not like Joseph bayed with a minimum of equipment.