Class 801 trains using diesel power.

[railwaytrack]

Normally only the 800 and 802 are referred to as bi mode units. However i understand that the 801 are actually bi mode too but i think they just have a very small engine or a very small fuel tank so it is only designed to be used in an emergency. My question is how often do the 801 operate on diesel power? When exactly is this used? How far can they get on diesel power? Is it enough for 801 to get between Ely and Peterborough during the Cambridge engineering work diversions? Do the 801 actually operate during the Cambridge engineering work diversions? I would be interested to know more about the diesel power of these units?

 

[boby32]

Normally only the 800 and 802 are referred to as bi mode units. However i understand that the 801 are actually bi mode too but i think they just have a very small engine or a very small fuel tank so it is only designed to be used in an emergency. My question is how often do the 801 operate on diesel power? When exactly is this used? How far can they get on diesel power? Is it enough for 801 to get between Ely and Peterborough during the Cambridge engineering work diversions? Do the 801 actually operate during the Cambridge engineering work diversions? I would be interested to know more about the diesel power of these units?

The class 801 are only emus not bi-mode units.

 

[railwaytrack]

The class 801 are only emus not bi-mode units.

But i thought that the 801 still have a small engine and small fuel tank used for emergencies so the train can still move without electric power? So surely this would make them bi mode units rather than pure EMU units?

 

[DanNCL]

Normally only the 800 and 802 are referred to as bi mode units. However i understand that the 801 are actually bi mode too but i think they just have a very small engine or a very small fuel tank so it is only designed to be used in an emergency. My question is how often do the 801 operate on diesel power? When exactly is this used? How far can they get on diesel power? Is it enough for 801 to get between Ely and Peterborough during the Cambridge engineering work diversions? Do the 801 actually operate during the Cambridge engineering work diversions? I would be interested to know more about the diesel power of these units?

801s (both 5 and 9 car units) have a single Diesel engine of the same specification as those found on the 800s. This is used routinely to allow access to unelectrified tracks in depots, as well as to allow self rescue should there be any issue that prevents the unit from using the available OHLE - under such circumstances the train would continue to the next station, and if it couldn’t continue on electric would usually be terminated. 801s are sluggish on their single Diesel engine, 40mph I think is the maximum speed they can reach on it.

9 car 801s are only diagrammed for work under the wires. 5 car 801s can, and often are during engineering work, be diagrammed to work away from the wires when working in multiple with a 5 car 800 - the 800 effectively dragging the 801 on the unelectrified part of the journey.

The class 801 are only emus not bi-mode units.

They’re considered as EMUs for diagramming purposes but they do have a single Diesel engine for emergency and depot use.

 

[hexagon789]

801s are sluggish on their single Diesel engine, 40mph I think is the maximum speed they can reach on it.

The Railway Performance Society has some logs published in an issue of Railway Magazine's Practice and Performance column from a few months ago, as well as extrapolating on the likely events behind the TPE ~145mph overspeed, the same article mentions that the balancing speeds on level track for the single-engine 801s is about 80mph for a 5-car and about 60mph for a 9-car. Acceleration is pitiful though, especially on the 9-car.

I believe originally they were going to be limited to running at 40mph on one engine, but it doesn't seem to have been imposed as a rule.

 

[AlistairCowell]

9 car 801s are only diagrammed for work under the wires. 5 car 801s can, and often are during engineering work, be diagrammed to work away from the wires when working in multiple with a 5 car 800 - the 800 effectively dragging the 801 on the unelectrified part of the journey.


They’re considered as EMUs for diagramming purposes but they do have a single Diesel engine for emergency and depot use.

Class 801 can also be propelled from the Class 800 from the back as well.

 

[Magdalia]

I don't pay much attention to these, except when they are diverted via Cambridge.

When that happens a bit more than half of the trains are 9 car units in the 800101-113 series, including all of the trains going through to to from Inverness and Aberdeen.

The remainder are 10 car trains formed of 2*5 car units. Every pair has at least one of 800201-210. Sometimes the other unit in the pair is also one of 800201-210, but more often it is one from 801101-112.

Make of that what you will!

 

[swt_passenger]

The remainder are 10 car trains formed of 2*5 car units. Every pair has at least one of 800201-210. Sometimes the other unit in the pair is also one of 800201-210, but more often it is one from 801101-112.

Make of that what you will!

When it’s a pair of 5 cars the 801’s power unit is only used for hotel services, the 800 is doing all the traction. This has been explained in previous threads about diversions away from the ECML, eg via Carlisle, and earlier in this thread by @DanNCL

 

[swaldman]

How much worse is the performance of 800+801 5-cars compared to a pair of 800s? I'd imagine doubling the weight without increasing engine power must hurt bad....

 

[hexagon789]

How much worse is the performance of 800+801 5-cars compared to a pair of 801s? I'd imagine doubling the weight without increasing engine power must hurt bad....

I think you mean a pair of 800s? Given the 800s are the full bi-modes, the 801s are the electrics with single "rescue" engine.

And yes it does hurt performance, tops out at about 80mph (eventually) a 10-car 800+801 combo on diesel.

 

[swaldman]

I think you mean a pair of 800s? Given the 800s are the full bi-modes, the 801s are the electrics with single "rescue" engine.

And yes it does hurt performance, tops out at about 80mph (eventually) a 10-car 800+801 combo on diesel.

Oops! I'll correct my question. But thanks for the answer anyway

Makes sense for diversions; do you know if any normal services are planned this way? I'd have thought that even in areas of low speed limits, the acceleration would be a problem...

 

[800001]

The Railway Performance Society has some logs published in an issue of Railway Magazine's Practice and Performance column from a few months ago, as well as extrapolating on the likely events behind the TPE ~145mph overspeed, the same article mentions that the balancing speeds on level track for the single-engine 801s is about 80mph for a 5-car and about 60mph for a 5-car. Acceleration is pitiful though, especially on the 9-car.

I believe originally they were going to be limited to running at 40mph on one engine, but it doesn't seem to have been imposed as a rule.

Highest speed for a 9 car 801 on diesel power in passenger service that I am aware of is about 54mph, that was a straight, level track.

 

[swt_passenger]

Oops! I'll correct my question. But thanks for the answer anyway

Makes sense for diversions; do you know if any normal services are planned this way? I'd have thought that even in areas of low speed limits, the acceleration would be a problem...

I think someone mentioned a while ago that an 800/801 pair were diagrammed for one of the un-electrified extensions in Yorkshire, but I can’t remember which thread it came up in. Clearly they have enough power to meet the line speeds on the Tyne Valley diversions. Not sure if that’s just luck or by design though…

 

[800001]

I think someone mentioned a while ago that an 800/801 pair were diagrammed for one of the un-electrified extensions in Yorkshire, but I can’t remember which thread it came up in. Clearly they have enough power to meet the line speeds on the Tyne Valley diversions. Not sure if that’s just luck or by design though…

They were for a short period diagrammed as an 800/801 pair on the Harrogate diagram.

Occasionally at the moment they do Kings Cross to Hull on a Saturday, usually a way of getting a set back to Doncaster.

 

[hexagon789]

Highest speed for a 9 car 801 on diesel power in passenger service that I am aware of is about 54mph, that was a straight, level track.

Railperf suggests 60 as a calculated balancing speed and sure enough in the April 2021 Railway Magazine Practice & Performance which features the 80x classes, there is an account of a 9-car 801 having to resort to diesel mode at Northallerton due to OLE issues. After switching to diesel, the train reached 50mph at Danby Wiske and eventually reached 60 (the highest recorded) at the Tees Bridge before slowing for Darlington. The unit was 801230.