View source for Prussian T 18

{{more footnotes|date=December 2014}}
{{Infobox locomotive
| name             = Prussian T 18 <br/>DRG Class 78.0–5<br/>PKP OKo 1
| bgcolor          = 000000
| color            = FFFFFF
| image            = 78 468 Dieringhausen.jpg
| caption          = 78 468 in Dieringhausen Railway Museum
| builder          = {{ubl|[[Stettiner Maschinenbau AG Vulcan]] (448)|[[Henschel & Sohn]] (80)|[[Hanomag]] (3)|[[Societe Franco-Belge]] (3)}}
| builddate        = 1912–1927
| totalproduction  = 534
| whytetype        = [[4-6-4T]]
| DRGtype          = Pt 37.17
| gauge            = {{Track gauge|1435mm}}
| leadingdiameter  = {{convert|1000|mm|ftin|frac=8|abbr=on}}
| driverdiameter   = {{convert|1650|mm|ftin|frac=8|abbr=on}}
| trailingdiameter = {{convert|1000|mm|ftin|frac=8|abbr=on}}
| over bufferbeams = {{convert|14800|mm|ftin|frac=8|abbr=on}}
| axleload         = {{convert|17.0|t}}
| emptyweight      = {{convert|83.2|t}}
| serviceweight    = {{convert|105.0|t}}
| weightondrivers  = {{convert|51.1|t}}
| tendertype       = 
| fuelcap          = {{convert|4.5|t|lb|abbr=on}} of coal
| watercap         = {{convert|12|m3|impgal USgal|abbr=on}}
| heatingtubes     = 134
| smoketubes       = 24
| heatingtubelength= {{convert|4700|mm|ftin|frac=8|abbr=on}}
| boilerpressure   = {{convert|12|kg/cm2|MPa lbf/in2|sigfig=3|abbr=on}}
| fireboxarea      = {{convert|2.44|m2|sqft|abbr=on}}
| radiativearea    = {{convert|13.04|m2|sqft|abbr=on}}
| evaporativearea  = {{convert|138.34|m2|sqft|abbr=on}}
| superheaterarea  = {{convert|49.20|m2|sqft|abbr=on}}
| cylindercount    = 2
| cylindersize     = {{convert|560|mm|in|frac=16|abbr=on}}
| pistonstroke     = {{convert|630|mm|in|frac=16|abbr=on}}
| locobrakes       = [[Compressed-air brake]]
| maxspeed         = {{ubl|to 78 009: {{convert|90|km/h|mph|0|abbr=on}}|from 78 010: {{convert|100|km/h|mph|0|abbr=on}}}}
| indicatedpower   = {{convert|1140|PS|kW hp|sigfig=3|abbr=on}}
| fleetnumbers     = DRG 78&nbsp;001&nbsp;– 78&nbsp;330,<br/>78&nbsp;351&nbsp;– 78&nbsp;528
| retiredate       = 1975
}}
The '''Prussian T&nbsp;18''' was the last class of [[tank locomotives]] developed for the [[Prussian state railways]]. They were originally intended for services on the island of [[Rügen]] as replacements for [[Prussian T 12|Class T 12]] and [[Prussian T 10|T 10]] engines. They emerged when a class of locomotive was conceived in 1912 that was to handle [[express train|express]] and [[passenger trains]] in border areas or in shuttle services on short routes. A tank engine design with symmetrical running gear was envisaged because, unlike a [[tender locomotive]], it could run equally fast forwards and backwards and could be operated on return journeys without having to be turned on a [[turntable (rail)|turntable]]. Its power and top speed were to be the same as those of the [[Prussian P 8|P 8]]. [[Robert Garbe]] designed this [[4-6-4]] (2′C2′) tank locomotive for 100&nbsp;km/h with a 17-ton [[axle load]] and contracted the ''Vulkan Werke'' in [[Stettin]] to build it. It was given the designation T&nbsp;18.

A total of 534 engines were built from 1912 to 1927, mainly by the [[Stettiner Maschinenbau AG Vulcan]] and, from 1923, also by [[Henschel]], of which 458 alone went to the [[Prussian state railways]] and, subsequently, the [[Deutsche Reichsbahn]]. The [[Royal Württemberg State Railways]] received 20 T 18s in 1919, the [[Imperial Railways in Alsace-Lorraine]] 27 also in 1919, the Saar Railway (''Saarbahn'') 27 between 1922–25 and the {{ill|Eutin-Lübeck Railway|de|Eutin-Lübecker Eisenbahn}} (''Eutin-Lübecker Eisenbahn'') one in each of the years 1936 and 1939.

The Reichsbahn took over 460 vehicles from [[Prussia]] and 20 from the Royal Württemberg State Railways, incorporating them into '''DRG Class 78''' with operating numbers 78 001–282 and 78 351–528. Of these, number 78 093 came from [[Alsace-Lorraine]] and numbers 78 146–165 from [[Württemberg]]. Later the engines from the Saar Railway were numbered 78&nbsp;283 to 78&nbsp;328 in 1935.{{sfnb|Weisbrod|1991|pp=36–37}} and those of the Eutin-Lübeck Railway as 78&nbsp;329 and 78&nbsp;330 in 1941.{{sfnb|Weisbrod|1991|p=199}}

The [[Deutsche Bundesbahn]] took over 424 engines and the [[Deutsche Reichsbahn in East Germany]] 53 examples. In 1968 only 35 engines remained with the DR in [[East Germany]]. In 1965 the DR fitted the majority of its engines with ''Giesl'' chimneys and '' Witte'' [[smoke deflectors]]. From 1968 the DB locomotives were reclassified into Class 078; in 1970 the DR regrouped its locomotives into Class 78.1.

The [[Polskie Koleje Państwowe|PKP]] took over some locomotives, classifying them as [[PKP Class OKo 1|OKo 1]].

The DB converted several Class 78s for push-pull running e.g. between [[Frankfurt am Main|Frankfurt]] and [[Wiesbaden]]. Because the engine driver in the driving coach could only work the brake, operation of the regulator and reversing gear was carried out by specially trained stokers as signalled by the engine driver. The last locomotives were retired by the DB in the mid-1970s at [[Rottweil]] locomotive depot (''[[Bahnbetriebswerk (steam)|Bahnbetriebswerk]]'' or ''Bw''). The farewell journey for this engine class and, at the same time for the Class 38s ([[Prussian P 8]]), took place on 31 December 1974. The event was organised by the ''Zollern Railway Friends''. The trip was even reported on the German television channel, ARD.

== Notable members ==

* {{Nobr|78 185}} was featured in [[The Great Escape (film)|''The Great Escape'']] hauling a train made up with Bavarian 3-axle coaches and some newer 2-axle steel coaches.<ref>{{Cite web|title=The Great Escape - Lobby card with Richard Attenborough & Gordon Jackson|url=https://www.moviestillsdb.com/movies/the-great-escape-i57115/675f75b2|access-date=2020-12-06|website=MovieStillsDB.com|language=en}}</ref> Other scenes depicting the same train were filmed with a [[DRG Class 86]] tank engine.<ref>{{Cite web|title=The Great Escape (1963) Filming Locations - Page 2 of 3|url=http://www.themoviedistrict.com/the-great-escape/2/|archive-url=https://web.archive.org/web/20190326091237/http://www.themoviedistrict.com/the-great-escape/2/|url-status=usurped|archive-date=March 26, 2019|access-date=2020-12-06|website=The Movie District|language=en-US}}</ref>

== Preservation ==

Several T 18 are preserved in museums:
*78 009 belongs to the [[Dresden Transport Museum]] fleet and is looked after by the ''IG Bahnbetriebswerk Dresden-Altstadt''.
*78 189, as '''OKo 1-3''' belongs to the [[Warsaw Railway Museum]] in [[Poland]].
*78 246 can be viewed at the [[German Steam Locomotive Museum]] (''Deutschen Dampflokomotiv-Museum'').
*78 468 (see photograph) belongs to the city of [[Oberhausen]] and is operational. It is run by the ''Emscher Park Eisenbahn Gesellschaft''.
*78 510 belongs to the [[DB Museum]]'s collection.

<gallery>
Image:78 1009-6 1.jpg| DR 78 009 in Potsdam (1993)
Image:OKo 1-3 Warszawa 06.04.05.jpg|OKo 1-3 ex 78 189 (Vulcan 3610 of 1920) 
Image:078 510-5 1.jpg| DB 78 510 in the [[Nuremberg Transport Museum]]
</gallery>

== See also ==
* [[Prussian state railways]]
* [[List of DRG locomotives and railbuses]]
* [[List of Prussian locomotives and railbuses]]

== Notes ==
{{Reflist}}

== References ==
* {{Weisbrod-EFA1.5|pages=36–37, 199–202}}

== Further reading ==
* {{cite book| last1=Ebel| last2=Knipping| last3=Wenzel| title=Die Baureihe 78, Bewährt in sechs Jahrzehnten: Preußens T 18| publisher=EK-Verlag| location=Freiburg| year=1990| isbn=978-3-88255-547-9| language=de}}
* {{cite journal| first=Dietmar| last=Falk| title=Die schnelle Preußin. Erinnerung an die T 18| journal=Lok Magazin| issue=265| volume=42| date=2003| publisher=GeraNova Zeitschriftenverlag GmbH| location=München| issn=0458-1822| pages=50–60| language=de}}
* {{Hütter-60bis91|pages=222–241}}
* {{Lohr-EFA2.6|pages=125–126, 166}}
* {{Vandenberghen-SNCB12.2|pages=352–353}}
* {{Weisbrod-EFA1.3|pages=88–90}}

{{Commons category|Prussian T 18}}

{{Prussian locomotives}}

[[Category:Railway locomotives introduced in 1912]]
[[Category:4-6-4T locomotives]]
[[Category:Locomotives of Prussia|T 18]]
[[Category:Standard-gauge locomotives of Germany]]
[[Category:Standard-gauge locomotives of Poland]]
[[Category:2′C2′ h2t locomotives]]
[[Category:AG Vulcan Stettin locomotives]]
[[Category:Passenger locomotives]]
[[Category:Henschel locomotives]]
[[Category:Hanomag locomotives]]
[[Category:Franco-Belge locomotives]]