Editing 4D (train) (section)

{{Short description|Melbourne prototype double deck electric multiple unit}}
{{Use dmy dates|date=December 2023}}
{{Use Australian English|date=October 2013}}
{{Infobox train
| name = 4D
| image = Melbourne 4D Train.jpg
| caption = 4D train at [[Southern Cross railway station|Spencer Street]], 2000
| interiorimage = Lower Deck 4D 5000M.jpg
| interiorimagealt = 
| interiorcaption = Lower deck Interior showing passenger seats and stairs
| service = 1992-2002
| manufacturer = [[UGL Rail|A Goninan & Co]]
| ordernumber = 
| factory = [[Broadmeadow]]
| family = [[Sydney Trains T set|Tangara]]
| successor = 
| yearconstruction = 
| yearservice = 10 March 1992
| yearretired = 25 February 2002
| yearscrapped = 30 March 2006
| numberbuilt = 1
| numberscrapped = 1
| formation = 4 carriages
| fleetnumbers = 6000T-5000M-5002M-6002T
| capacity = 346 seated, 628 standing
| operator = [[Public Transport Corporation]]
| depots = [[Bayswater railway station, Melbourne|Bayswater]]
| lines = {{rcb|Melbourne|Lilydale|croute}} {{rcb|Melbourne|Belgrave|croute}}
| carbody = [[Stainless steel]]
| trainlength = 
| carlength = {{convert|20.32|m|ftin|abbr=on}}
| width = {{convert|2.89|m|ftin|abbr=on}}
| height = {{convert|4.27|m|ftin|abbr=on}}
| floorheight = 
| platformheight = 
| entrylevelorstep = 
| doors = 4 twin-leaf plug doors per carriage
| wheeldiameter = {{convert|940|mm|in|0|abbr=on}}
| wheelbase = 
| maxspeed = {{convert|130|km/h|mph|abbr=on}}
| weight = {{convert|186|t}}
| axleload = 
| traction = [[Mitsubishi Electric|Mitsubishi]] [[Gate turn-off thyristor|GTO]]–4-quadrant [[Chopper (electronics)|chopper]] control
| traction motors = 8 × Mitsubishi MB-3303-B {{convert|170|kW|abbr=on|0}} 2-phase DC [[Brushed DC electric motor#Shunt wound motor|shunt-wound motor]]
| poweroutput = {{convert|1360|kW|0|abbr=on}}
| transmission = 4.94:1 (84:17) gear ratio<ref>{{cite web |title=Technical Report Vol.62 No.6 |url=https://www.giho.mitsubishielectric.co.jp/giho/pdf/backnumber/1988(vol62)/Vol62_06.pdf |website=[[Mitsubishi Electric]] |access-date=3 July 2024 |pages=53 - 58 |language=ja |date=June 1988}}</ref>
| acceleration = {{convert|0.75|m/s2|abbr=on}}
| deceleration = 
| aux = [[Toshiba]]
| hvac = 
| electricsystem = {{1,500 V DC}} (nominal) from [[Overhead line|overhead catenary]]
| collectionmethod = [[Pantograph (transport)|Pantograph]]
| uicclass = 2′2′+Bo′Bo′+Bo′Bo′+2′2′
| bogies = [[Nippon Sharyo]] bolsterless<ref>{{cite book |last1=Allen |first1=Geoffrey Freeman |title=Jane's World Railways 1991-92 |date=1 November 1991 |publisher=Jane's Information Group |isbn=9780710609557 |page=75 }}</ref>
| brakes = 
| safety = 
| coupling = [[Scharfenberg coupler]]
| multipleworking = 
| gauge = {{track gauge|1600mm|lk=on}}
}}

The '''4D''' was a prototype [[bilevel rail car|double deck]] [[electric multiple unit]] built for the [[Public Transport Corporation]] in [[Victoria, Australia]], for operation on the [[Railways in Melbourne|Melbourne railway system]]. It remains the only double deck train to have ever operated in Melbourne. The train's name stood for "Double Deck Development and Demonstration."<ref>{{Cite web|url=http://vicsig.net/index.php?page=suburban&section=4d|title = VICSIG}}</ref>

Depending on sources, the intention was for this train to be the demonstration unit for a future order of either 20 or 50 extra sets, had the tests been successful.{{citation needed|date=July 2023}}