Refuelling of Diesel multiple unit engines

[anamyd]

I'm just wondering, with Diesel multiple units (DMUs) that consist of two or more vehicles of course having multiple engines, are the engines refuelled one-by-one, or simultaneously?

For example, the longest DMUs in Britain to my knowledge are the four 7-car 222s. With those, is there one person going along refuelling all 7 engines one-by-one (seems like that would be very time-consuming, but maybe that's just the work involved?) or are there 7 fuel pumps and 7 people, refuelling all the engines simultaneously? (I can't imagine that there are, seems unlikely).

 

[JonathanH]

Modern depots are built with multiple fuelling points corresponding with the fuel point on each carriage. You can see them if you pass Selhurst depot between East Croydon and Norwood Junction, among other locations.

This is an aerial view of the fuel road at Selhurst Depot showing six fuelling points.

[Picture shows six canopied fuelling points on a siding adjacent to the running lines between East Croydon and Norwood Junction.]

 

[Big Jumby 74]

Modern depots are built with multiple fuelling points corresponding with the fuel point on each carriage.

That is one of the critical points about modern day/more recent depot facilities. Having been involved in SWT 159 diagramming, we had the optimum situation at Salisbury depot, purpose built for the traction type, but with engineering work scenarios, the revised train plan could lead to units being isolated at Exeter. One unit was always stabled there in the base plan, last arrival from Waterloo, first departure next day (05.10), but this diagram was designed such that it wouldn't need any attention at Exeter, other than an internal sweep of public litter.
In my time there was a plan to look at refuelling of 159s at St Davids, but at the time in question (AFAIR) this was deemed unworkable, as the spacing of fuel lines on the shed didn't match with the cars (of a 159), and so, given the time span that any such unit would have on shed, based on the timetable of arrival/departure at St Davids, from/to Waterloo, the idea was ditched. Something in the back of my head says there was also a problem with the physical hose to unit connection, but I wasn't that close to the discussions to understand the wider picture.

 

[paulmch]

At Coldhams Lane depot in Cambridge, they can refuel 2 vehicles at once, so if you have more than 2 vehicles the driver will move the train under instruction from somebody stood at the fuel point making sure the train is lined up with the fuel pumps correctly. It's a pretty tedious process, especially as it usually comes at the end of a long afternoon shift!

 

[scotraildriver]

This has been part of the issue with ScotRail's HSTs. All the depots are set up for multiple units with the fuelling points aligned accordingly. As a result the HSTs have to be fuelled 1 power car at a time and in some locations the 5 car sets foul the fuel roads preventing anything else moving whilst the fuelling is taking place. It can cause real delays getting trains to the depots at the end of the day.

 

[anamyd]

Many thanks for the replies everyone

 

[AirRail]

Whilst on the subject of fuelling if you dont mind me jumping in... Are the fuel tanks always filled to full as an industry standard each time ? Or could this be something different per each operator / even planned diagram dependant? I know its not the same as an aircraft, for example where payload restrictions and reducing weight to save fuel burn completely applies. However, its just a thought, , as potentially some units (particularly locos) can hold significant amounts of fuel in their tanks. If a full full tank was not always required, maybe they could save some weight for better fuel usage / engine wear ?

 

[6Gman]

Whilst on the subject of fuelling if you dont mind me jumping in... Are the fuel tanks always filled to full as an industry standard each time ? Or could this be something different per each operator / even planned diagram dependant? I know its not the same as an aircraft, for example where payload restrictions and reducing weight to save fuel burn completely applies. However, its just a thought, , as potentially some units (particularly locos) can hold significant amounts of fuel in their tanks. If a full full tank was not always required, maybe they could save some weight for better fuel usage / engine wear ?

Certainly in my time fuel tanks would be filled to capacity. Half-filling for light duties might seem a good idea, but set swaps would then create all sorts of problems!

 

[ChiefPlanner]

Whilst on the subject of fuelling if you dont mind me jumping in... Are the fuel tanks always filled to full as an industry standard each time ? Or could this be something different per each operator / even planned diagram dependant? I know its not the same as an aircraft, for example where payload restrictions and reducing weight to save fuel burn completely applies. However, its just a thought, , as potentially some units (particularly locos) can hold significant amounts of fuel in their tanks. If a full full tank was not always required, maybe they could save some weight for better fuel usage / engine wear ?

In my day - as a mere operator not a fleet person , tanks were always fully filled on depots (and of course monitered on various computer services) - part of the preparation duties from berth was a check on the fuel gauges. "Fleet" did not like stock running around on low fuel levels for obvious reasons.......

 

[skyhigh]

Always filled to full.

 

[Blindtraveler]

What a really interesting thread. Thank you for posting it

 

[Big Jumby 74]

Filled to full normally the rule. As has been mentioned above, any disruption and a lightly fuelled unit could end up on a near maximum mileage diagram - not good! In the case of 159's in my time, the maximum diagrammed mileage was 1600 miles between fuelling. They could go a bit further, but a sensible cut off point has to be agreed and adhered to . I believe that figure has more recently been lowered to 1500, although can't confirm that. In generic terms it would mean most units would run for two days (IIRC) between trips on shed and refuelling. The depot through put of units was (still is I guess) a very finely tuned and expertly executed plan given the limited space available.

 

[Vespa]

It's always better to go out full, if you run out of diesel it's not just a case of filling up and go, you need to prime the diesel engines before starting.

Like diesel engine in cars, it will not start from empty until primed, some newer cars have diesel uplift from tanks to engine to ensure it will start after empty.