Class 80X Technical

[ZakCreaser2003]

Hi All,

Hope we are well. As a train enthusiast who adores the Hitachi Class 80X family, I am curious about the technical side of these units. I would be grateful if anyone could answer the following questions?

- What equipment is housed in the black / grey boxes under the coaches?
- What is the scheduled exams undertaken on these units?

Many Thanks

 

[Rob F]

I would like to add a question that I don't think I have seen an answer to:

• When running on diesel, does the genset only power the traction motors on the vehicle it is housed in or is there a 'power bus'. i.e if a vehicle is running with its genset not working, are its motors still powered?

 

[Snow1964]

The under coach boxes are partly there for aerodynamics so that there is not turbulence underneath the coaches. So some of the space is unused (or a small unit in a big standard space).

Various equipment depending on the vehicle, at the ends are toilet retention tanks. Between bogies there is diesel-generator sets (and possibly in future batteries), compressors for air brakes, air conditioning and ventilation units, 25kv transformer (but not in same vehicle as a diesel engine), power electronics to control motors, battery for emergency lights, etc.

From memory there is some dead weight ballast in outer ends, so if it hits a fallen tree branch etc, sufficient weight to keep it on rails if possible

 

[AndrewE]

Hi All,

Hope we are well. As a train enthusiast who adores the Hitachi Class 80X family, I am curious about the technical side of these units. I would be grateful if anyone could answer the following questions?

- What equipment is housed in the black / grey boxes under the coaches?
- What is the scheduled exams undertaken on these units?

Many Thanks

Have you looked at the Wikipedia pages?
https://en.wikipedia.org/wiki/British_Rail_Class_802 and https://en.wikipedia.org/wiki/British_Rail_Class_810

 

[driver9000]

Depending on the variant and which vehicle you're looking at you'll find the heavy equipment under there such as engines, transformers, auxiliary power units, compressors, toilet retention tanks, air suspension tanks, main air reservoir tank and a host of other equipment the unit needs to run.

== Doublepost prevention - post automatically merged: 11 Dec 2024 ==

I would like to add a question that I don't think I have seen an answer to:

• When running on diesel, does the genset only power the traction motors on the vehicle it is housed in or is there a 'power bus'. i.e if a vehicle is running with its genset not working, are its motors still powered?

Each engine powers the vehicle it's fitted to. No engine running means no traction power to that vehicle.

 

[JamesT]

Each engine powers the vehicle it's fitted to. No engine running means no traction power to that vehicle.

Do you have a reference for that? That's how the Voyagers work, but the 80X have a power bus running along the train.

 

[Ashley Hill]

Do you have a reference for that? That's how the Voyagers work, but the 80X have a power bus running along the train.

For when on electric. On diesel, no engine then no traction power to that car, only passed through to the auxiliaries from other engines.

 

[driver9000]

Do you have a reference for that? That's how the Voyagers work, but the 80X have a power bus running along the train.

I sign Bi-Mode 802s. They can cross feed some auxiliaries to an adjacent vehicle but traction power isn't cross fed and is noticeable with the train performance. There is a Limited Traction option within Rescue Mode which to my knowledge (having never used it) only applies to the electric 80x fitted with the donkey engines to feed 8 motors through 2 Traction Converters.

 

[class ep-09]

For when on electric. On diesel, no engine then no traction power to that car, only passed through to the auxiliaries from other engines.

That may not be true .
TMS shows traction motor torque still being applied in a vehicle, where genset is not running / faulty , suggesting traction power is still available to traction motors in that coach from other coaches ( but limited) .
However , there is possibility for the genset “power supply” to be isolated , then traction motor torque shows “0” on that vehicle.
Either way - train will have slower acceleration.

 

[littledude]

A GU being isolated removes traction power from that vehicle, so on a 9 car the GUs are on vehicle 2, 3, 5, 7 and 8, and guess which vehicles have traction motors!

Likewise a traction converter being isolated on a vehicle will prevent that vehicle providing power/dynamic braking, but doesn’t affect adjacent vehicles.

The only traction power bus along the length of the train is the 25kV line at roof height, fed through VCB1 of whichever pantograph is raised, then down through VCB2/3 to the transformers.

The APS (auxiliary supply) output technically runs the length of the train, a 5 car has 2 APS (vehicles 1 and 5) and a 9 car has 4 (vehicles 1, 4, 6 and 9) - when the APS are all happy and in harmony, the BKK contractor energises which allows them all to load share. This contactor will open if there is any phase difference between any of the APS.

 

[43096]

The only traction power bus along the length of the train is the 25kV line at roof height, fed through VCB1 of whichever pantograph is raised, then down through VCB2/3 to the transformers.

Presumably there is a traction power bus between vehicles from the transformers to the cars with traction motors?

 

[stuving]

Presumably there is a traction power bus between vehicles from the transformers to the cars with traction motors?

I was expecting these trains (the electric ones) to follow the standard pattern, with the transformer and 1-phase AC-DC converter close to the pantograph, feeding a DC bus with all the traction converters (3-phase inverters) connected to it. Generators in the bi-modes could then feed that bus via an AC-Dc converter.

But when I saw one (a GWR bi-mode) up close, it looked wrong for that pattern. There are (famously) a lot of cables between the carriage ends, especially the driving trailers. I counted 16 on one side; there may be the same on the other. And they are marked as 1800(DC)/3000(AC) V and 150 sq m, which I reckon should carry about 200A (or probably a bit less). Each motor drive converter (for four motors) needs more than 900 kW, and there are more of them than there are transformers, so several of those cables are needed to supply that.

Now this power stuff is not my field, but I'm pretty sure you can't safely parallel such short cables - they can't be relied on to share current nicely. So I can only guess that each cable runs point-point from source to load, through several vehicles in some cases. But how is the power added together at the load end? Well, another non-standard feature is described in a Hitachi paper: the same motor drive converter is fed from the GU (as 3 phase) or from the transformer (as 1 phase). So maybe each input to that converter, via an IGBT circuit, has its own cable from the transformer, all in phase with each other.

 

[Energy]

Image Description - Diagram of the Traction/Auxilliary Power System. Credit: Hitachi.


The driving cars contain a pantograph and a transformer. The AC bus is roof mounted and you can see the pigtails between vehicles.

Each motor vehicle can either take off this bus or use its local generator to feed the drive converter and the auxiliary power system. The auxiliary bus is normal 400V 3 phase (individual phases are 230V) and spans the entire train length, allowing trailer and failed motor vehicles to get auxiliary power of the bus.

The traction packs feed 4 226kW motors each, these use open-air ventilation for cooling. Every axle of the motor car is powered and the trains are rather quick on electric but the diesel engine can't really keep up.

The design is pretty much the same as the class 395, just with a generator unit instead of third-rail shoes.

Presumably there is a traction power bus between vehicles from the transformers to the cars with traction motors?

Its a general AC power bus rather than specifically traction power. Motor cars can't crossfeed traction power from power packs though. Not that they'd need to, auxiliary power is shared and the engines can't fully power the motors on their own vehicles, let alone neighbouring ones.

 

[norbitonflyer]

I wouldf guess there is little point in transferring power generated on board from one power car to another, as the total amount of power available to the train wouldn't be improved - you would just have five power cars each running at 80% power instead of four running at 100%.

 

[Rob F]

A follow on question. On the class 810 there are four genset vehicles but only two motored cars. Does each genset independently supply a single bogie under the motored cars or is it more complicated?

 

[100andthirty]

A follow on question. On the class 810 there are four genset vehicles but only two motored cars. Does each genset independently supply a single bogie under the motored cars or is it more complicated?

In a word - yes!

 

[david.stannard]

Interesting discussion about there being no traction power bus to transter power between vehicles when operating in diesel mode. Two queries:
1) Thought that I had seen comments about a 'rescue' mode for 802s on low diesel power, I had assumed perhaps to distribute the available tractive effort down the set. Presumably not, so does such a mode exist and if so what does it entail?
2) On the TPE 802 battery test set it was said battery recharge was possible when running in electric mode under the wires (fair enough using the AC bus) but also from regeneration when braking. So if braking in diesel+battery mode does that imply battery recharge is only from one vehicle and not three?

 

[stuving]

Image Description - Diagram of the Traction/Auxilliary Power System. Credit: Hitachi.

That diagram is from the article I was talking about (not really a technical paper). In the text, it says this about the diagram:

Fig. 7 shows an overview of the traction and auxiliary power supply (APS) system. The system can select the appropriate power source from either the main transformer or the GUs. Also, the size and weight of the system were minimized by designing the power supply converter to be able to work with both power sources.

 

[Elecman]

. I counted 16 on one side; there may be the same on the other. And they are marked as 1800(DC)/3000(AC) V and 150 sq m, which I reckon should carry about 200A (or probably a bit less).

150sqmm cable will safely carry 300amps