GNRI Class P

{{Infobox locomotive }} Great Northern Railway Class P were two sets of 4-4-0 locomotives for the Great Northern Railway of Ireland (GNRI) introduced from 1892 by locomotive superintendent J.C. Park; four having {{Convert|6|ft|7|in|m|abbr=on}} driving wheels and eight having {{Convert|5|ft|7|in|m|abbr=on}} driving wheels. Park was succeeded by Charles Clifford who constructed 17 broadly similar locomotives from 1896 with {{Convert|6|ft|7|in|m|abbr=on}} driving wheels; these were designated Class PP.{{Sfnp|Johnston|1999|pp=70–71, 76–77}} The last PP class survived until 1963.{{Sfnp|Johnston|1999|p=77}}
 * name            = Great Northern Railway Classes P & PP
 * powertype       = Steam
 * image           = GNRI PP Class No. 107 Cyclone locomotiverailwa1219unse-p77 (1906 photograph).png
 * alt             =
 * caption         =
 * designer        = {{ubl|{J.C. Park|C. Clifford}}
 * builder         =
 * ordernumber     =
 * serialnumber    =
 * buildmodel      =
 * builddate       = {{ubl|1892(P)|1896(PP)}}
 * totalproduction = 29{{efn|Four Class P with 6' 7" wheels, and eight with 5' 7" wheels; Seventeen Class PP with 6' 7" wheels}}
 * rebuilder       =
 * rebuilddate     =
 * numberrebuilt   =
 * whytetype       = 4-4-0
 * uicclass        =
 * gauge           = {{track gauge|5ft3in|lk=on}}
 * driverdiameter  = {{ubl|{{convert|6|ft|7|in|mm|0|abbr=on}}|{{convert|5|ft|7|in|mm|0|abbr=on}}}}
 * minimumcurve    =
 * wheelbase       =
 * length          =
 * width           =
 * height          =
 * axleload        =
 * weightondrivers =
 * locoweight      =
 * tenderweight    =
 * locotenderweight =
 * tendertype      =
 * fueltype        =
 * fuelcap         =
 * watercap        =
 * tendercap       =
 * sandcap         =
 * boiler          =
 * boilerpressure  = {{Convert|175|lbf/in2|kPa|2|abbr=on}}
 * feedwaterheater =
 * firearea        =
 * tubearea        =
 * fluearea        =
 * tubesandflues   =
 * fireboxarea     =
 * totalsurface    =
 * superheatertype =
 * superheaterarea =
 * cylindercount   = Two, inside
 * cylindersize    = {{Ubl|{{Convert|17|x|24|in|mm|abbr=on}}{P)|{{Convert|18|x|24|in|mm|abbr=on}}(PP)}}
 * valvegear       =
 * valvetype       =
 * valvetravel     =
 * valvelap        =
 * valvelead       =
 * transmission    =
 * maxspeed        =
 * poweroutput     =
 * tractiveeffort  = {{convert|13840|lbf|kN|2|abbr=on}}−{{convert|15340|lbf|kN|2|abbr=on}}
 * factorofadhesion =
 * trainheating    = steam
 * locobrakes      =
 * locobrakeforce  =
 * trainbrakes     =
 * safety          =
 * operator        = GNR(I) → UTA → CIÉ
 * operatorclass   =
 * powerclass      =
 * numinclass      = 29
 * fleetnumbers    = 12, 25, 42–46, 50, 70–71, 74–77, 106–107, 129
 * officialname    =
 * nicknames       =
 * axleloadclass   =
 * locale          =
 * deliverydate    =
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 * retiredate      =
 * withdrawndate   =
 * preservedunits  =
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 * currentowner    =
 * disposition     =
 * notes           = {{Sfnp|Boocock|2009|p=65}}