That’s like cheating.
I’m not sure how useful an electric bike would be since distance from Durango to Silverton is over 40 miles according to Google maps. And if I recall, there are two fairly high passes to cross, so may run out of juice before getting there. Not sure if those bikes have regen like electric cars to recharge on way down.
I think to beat the train, bikes have to finish in under 4 hours. That doesn’t seem like much except when you figure climbing elevation and pedaling at those high altitudes. It’s a lot tougher challenge than it sounds, specially for flat landers.