Would you mind getting the engines with detachable, non-powered tenders (Donald, Douglas, Spencer, Neville) or tender driven ones (Emily, Murdoch, Molly), or are you specifically looking for those with the permanent battery tender design (Edward, Henry, Gordon, James)? I really dislike the way the last four work due to the flimsy wire coupling. Shame Gordon was never updated before the 2014 TrackMaster redesign.