Talk:GSR Class 800

Maedhbh or Macha?
Anybody heard the story that it's actually the Macha preserved in Cultra? According to legend, Macha was in better condition than Maedhbh at the end, so was sent for preservation instead, carrying Maedhbh's nameplates. Talk about 9/11 conspiracy theories. Suckindiesel (talk) 20:58, 29 April 2009 (UTC)

Didn't hear that. My Grandfather worked in the Inchicore works and worked on the maintenance and manufacturing of all 3 engines. Shortly before he died in 1969, he went up to the Ulster Museum to see the Maedhbh. I'm sure he would have noticed if it wasn't what it's supposed to be. —Preceding unsigned comment added by 89.124.242.112 (talk) 19:44, 29 October 2009 (UTC)

Full potential of Irish Gauge
What about the full potential of locomotives on other railways using the Irish Gauge?


 * Brazil
 * Victoria

Tabletop (talk) 05:24, 30 October 2009 (UTC)


 * That's a good point. I'd suggest the Victorian Railways H class would be a better example of a locomotive exploiting the extra width afforded by 5'3" gauge, but are we confusing rail gauge with loading gauge? Any inside cylindered broad gauge steam locomotive with reasonably large diameter cylinders could arguably be said to have exploited the benefits of the extra six and a half inches of Irish gauge over standard gauge.


 * Maybe the editor was suggesting that this class was the first in Ireland that had the potential to realise some of the benefits of a broader gauge (such as stability at speed, etc). Zzrbiker (talk) 13:38, 29 November 2009 (UTC)

Power section
I'm not sure the "Power" section which was added in this edit really adds much to the article. Apart from the fact that formulae for determining the power of steam locomotives are going to apply to all steam locomotives and not just this class (so why would such a discussion appear in this article only), it appears to be original research (see WP:NOR). Zzrbiker (talk) 13:19, 29 November 2009 (UTC)
 * Yes, it's not specific to this loco, should be removed & possibly incorporated in Tractive force. An interesting discussion of the topic, all the same. Suckindiesel (talk) 18:01, 29 November 2009 (UTC)

Moved from main article
Tractive effort (TE) is the name for the force applied to the rail by the wheel of the train to cause movement. Thus Maeve's force of 34,799 pounds-force equates to 154.8 kN. TE is not constant throughout the speed range but reduces as the engine speeds up.

The TE is constant typically from stall speed up to 20 mph (29.3 ft/s or 8.9 m/s) and during this time acceleration is constant. This is the region of maximum tractive effort and is indicative of the maximum output capability of the engine.

Power is measured as force times speed; hence the maximum power capable can be calculated from the maximum speed attained at the maximum tractive effort.


 * Force (154.8 kN) × speed (8.9 m/s) = 1380 kW
 * Force (34,799 lbf) × speed (29.3 ft/s) = 1,019,611 ft·lbf/s. Since a horsepower is 550 ft·lbf/s, dividing by that gives 1854 hp

Thus 1854 hp is the theoretical maximum power at rail.

Note that the actual power to the rail will be reduced due to friction, air resistance (drag), and power dissipated in sound, heat etc. In effect, Maedhbh probably had similar tractive effort to a GM refitted A Class.

External links modified
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