Probably railtours that were never implemented or are seasonal, one for the class 40 the other queen's jubilee themed. Remember at the time this route was built, they'd probably not thought the layer name would be visible publically like this.
I definitely really like the fact we get layer information now, it'll help me decide what to purchase in sales down the line to enhance the routes i play most often however i would like it to be made clearer exactly what layers are available and exactly which dlc unlocks them.. i'd like to think this is something that dtg could look into as it's in their interests, as having these layer lists will likely encourage more purchases than would otherwise be made!