In 12 inch to the foot gauge, it appears from the various writings that slide valves were not too good with superheated steam. Why? Just to complicate matters, a lot of the GC Pom poms had slide valves and superheated steam,and they were not an unsuccesful design, especially considering the longevity of the class. In the late 1950's, it was usually a Pom pom on the 4.50 from Retford to Sheffield; not a very well patronised service from Retford to Worksop, and so it was good for clandestine meetings with the girls from the High School. Strange how age gets you: I remember more of what the Pom pom s looked like than the individual girls! Peter Chadwick, Swindon ---------- Zarlink Semiconductor Limited is a Company registered in England and Wales under number 00705031 with its registered office at Cheney Manor, Swindon, Wilts SN2 2QW, England. This email is confidential and may contain information that is privileged and exempt from disclosure by law. If you have received it in error, please contact the sender immediately by return email and then delete it from your system; you should not copy it or disclose its contents to anyone. Emails are not secure and cannot be guaranteed to be error free as they can be intercepted, amended, lost or destroyed, or contain viruses. Anyone who communicates with us by email is taken to accept these risks. MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.