Ah yes--maybe on the SVR in to-day's economic climate but not when I was on the footplate back in the 1980's... !!......However even then we were trying sample coal from Poland and South America.. This was known as "Young" coal and carried a lot of clay, Ash and Clinker....Typically they were from open cast mines and cheap, in every way...I use Welsh Steam coal in my 5"gauge GWR locos, admittedly at vast cost pro rata, but it's worth it !!
