antique railroad locks, iron padlocks w/ brass lock cover, primitive heart shape

Collection of four vintage iron padlocks with heart shapes, three with brass face plates at the keyholes. (Two have key hole covers, one of these marked W. W. (William Wilcox?)

We've been told these are really old railroad locks, but aside from that we don't know much about them. All have finish wear, but aren't rusty at all. We have no keys for any of these.