For anyone looking for a relevant source to "but those 8 represent far less than half of the affected workforce." I don't have that but I will offer this

If you want the cliff notes rather than read it, it mentions that BLET, possibly the second largest from what I've seen, with about 24,000 voted to accept the offer by about 53.5%. The largest, about 28,000, voted against 50.87%. Total union rail workers looks to be around 115,000. Really calls the claim into question so I'll wait here for the source that backs it up since I apparently know "dick about dick".