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MellishR's Recent Activity

  1. MellishR liked Sheff's post in the thread 6024 King Edward 1.

    I was an engineer in the chemical industry all my working life and firstly for our sins they were always referred to as vacuum pumps, be they recip, liquid ring or whatever. However, in design and specification, we always used absolute pressure...

    Jun 1, 2026 at 8:16 PM

  2. MellishR liked GW 5972's post in the thread 6024 King Edward 1.

    I’m not going to comment on the cause of the squeak in case it leads to another forty posts!!!

    Jun 1, 2026 at 8:15 PM

  3. MellishR liked Wenlock's post in the thread 6024 King Edward 1.

    It is labelled both Air Pump and Vacuum Pump. I suppose it could be called the "Vacuum Maintaing Air Pump" :) But what really matters is, why does it squeak? Is that a fault, or is it an indication of a good seal around the piston?

    Jun 1, 2026 at 8:15 PM

  4. MellishR liked Jamessquared's post in the thread 6024 King Edward 1.

    Yes, but we’d also put a liquid nitrogen trap in the circuit between pump and vacuum line to prevent the pump oil absorbing volatiles and reducing the efficiency, and I’d like to see the Swindon drawing for that! Tom

    Jun 1, 2026 at 8:15 PM

  5. MellishR liked 26D_M's post in the thread 6024 King Edward 1.

    To be further pedantic, the "pump" maintains the vacuum, created by a steam ejector, once on the move ....

    Jun 1, 2026 at 8:13 PM

  6. MellishR liked Deepgreen's post in the thread Steam Dreams 2026.

    Perhaps edging towards the situation where patrons can only dream of steam!

    Jun 1, 2026 at 7:58 PM

  7. MellishR replied to the thread 6024 King Edward 1.

    I'm ready to out-pedant the best of them but, as the reason for the pump's existence is to create a (partial) vacuum, I see nothing wrong with calling it a vacuum pump.

    May 31, 2026 at 6:26 PM

  8. MellishR liked torgormaig's post in the thread 6024 King Edward 1.

    So is it a vacuum pump, or is it an air pump? Is it a railway station or is it a train station? In both situations we all know what people are talking about and as far as I can see both terms are correct in their respective situations. On the...

    May 31, 2026 at 6:23 PM

  9. MellishR replied to the thread Saphos Trains 2026.

    If a rake includes even one coach with aircon it will need to include either a diesel or a generator car.

    May 30, 2026 at 3:59 PM
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