Class 380

[Bayum]

So I've been watching a video of trains at a place called Prestonpans, and came across the class 380.

I've seen and read about them before, but something struck me - and I'm sure it will be a part of other stock as well.

In the videos, the undercarriage of one of the coaches is bare - there's nothing there at all!

Why is this?

Is it just the way the rolling stock was built?

http://www.youtube.com/watch?feature=player_detailpage&v=iMt0k9UOp2w#t=436


The above is the video I was watching which shows what I mean.

 

[Crossover]

On mobile so difficult to watch the video but I think I know what you mean. It just has little equipment under the coach. Unlike diesels that often have an engine under each, electrics don't have duplicate equipment on each coach. What is on it is likely to be air con units and such bit not much else. It is a fairly common feature of EMUs

 

[user15681]

For those of you that don't want to watch the entire video to see what the OP means, there's a perfect example around 07:20 in the video above.

 

[MK Tom]

I notice this with 350s quite a lot. They seem to have far less under there than most EMUs.

 

[starrymarkb]

All the Siemens EMUs working in the UK so far have 2 powered vehicles (the driving cars). The unpowered trailers do tend to have very little underneath.

Bombardier stuff tends to have n-1 powered cars (where n is the number of vehicles in the train) with the unpowered car having a transformer (or ballast equivalent to one for DC only units)

 

[fgwrich]

All the Siemens EMUs working in the UK so far have 2 powered vehicles (the driving cars). The unpowered trailers do tend to have very little underneath.

Bombardier stuff tends to have n-1 powered cars (where n is the number of vehicles in the train) with the unpowered car having a transformer (or ballast equivalent to one for DC only units)

Having been lucky to have a look under several Siemens Desirio EMUs, they are rather impressive underneath - A lot of the technology are concentrated in certain areas, leaving one coach with just the necessary air tanks and small compressor for it. Coupled to the 'Fly by Wire' and modular technology Siemens are using and it's likely we'll see even less in the future. Each Desiro bogie is rather impressive if not 'hulky' piece of kit too.

 

[ryan125hst]

Looking at that video, I'm guessing that the under floor equipment is something like this:

• Driving cars: Traction inverter and motors, air tanks.
• Trailer vehicle: Air tanks
• Pantograph vehicle: Transformer, rectifier, air tanks, maybe a compressor (don't know which carriage/s the air compressor is in.

The vehicles containing a toilet will also have a CET tank underfloor. The air conditioning units are on the roof on modern trains (Turbostars, Electrostarts, both diesel and electric Desiro's), so that's one less thing under the floor.

The above is only a guess as I can't find any confirmations online. Wikipedia does mention the equipment locations on a Class 377 though (presumably 375/6/8/9's and 357's will be similar, the only difference being the number of cars (with some having four, so no MOS and some having three so no MOSL either), and the fact that the 376's and 378's don't have toilets. Note that where there are motors, there will also be a traction inverter, and only AC versions of the class will have a pantograph and transformer/rectifier.

The configuration of a 5-car Class 377 unit is:

• DMOS(A) - 2 motors on inner bogie, sander, auxiliary converter module
• MOSL - 2 motors on inner bogie, standard toilet
• PTSOL - pantograph, transformer, compressor, disabled toilet
• MOS - 2 motors on inner bogie, standard class interior (at present this is only found on class 377/6 units)
• DMOS(B) - 2 motors on inner bogie, sander, auxiliary converter module

http://en.wikipedia.org/wiki/British_Rail_Class_377

 

[fgwrich]

Looking at that video, I'm guessing that the under floor equipment is something like this:

• Driving cars: Traction inverter and motors, air tanks.
• Trailer vehicle: Air tanks
• Pantograph vehicle: Transformer, rectifier, air tanks, maybe a compressor (don't know which carriage/s the air compressor is in.

The vehicles containing a toilet will also have a CET tank underfloor. The air conditioning units are on the roof on modern trains (Turbostars, Electrostarts, both diesel and electric Desiro's), so that's one less thing under the floor.

Not on the Desiro's they aren't as they're built into the trains. Bombardier's stock does have underfloor CET tanks although constructed in a typicaly cack-handed way whereby the tank is further under the train (both 'bogs' in Siemens and Bombardiers rolling stock are above the bogies).

 

[Crossover]

Having been lucky to have a look under several Siemens Desirio EMUs, they are rather impressive underneath - A lot of the technology are concentrated in certain areas, leaving one coach with just the necessary air tanks and small compressor for it. Coupled to the 'Fly by Wire' and modular technology Siemens are using and it's likely we'll see even less in the future. Each Desiro bogie is rather impressive if not 'hulky' piece of kit too.

Although I haven't been under any of the Desiros, I have been to Ardwick Depot and seen the 185's up close. It was mentioned at the visit as to how modular everything is, and bits literally bolt on/off the frame with the use of drops. There was a soare engine module out to one side for us to see to illustrate the point

 

[The_Stig]

The class 380's have 2 main compressors, each in the DMOS vehicles.

The coach with virtually no equipment is under the TOSL. Its just brake equipment and a few air tanks on the under frame.

The basic 380 make up is-

DMOSA/B- 4 motors (one on each axle, bogie mounted), Main compressor, brake equipment, Traction pack (converting the DC from the ACU's to AC for the motors), Sanders and air tanks.

PTOSLW- Main transformer, brake equipment, Batteries, ACU1 & 2, Auxiliary compressor and ar tanks.

TOSL- Brake equipment & air tanks.

 

[swt_passenger]

For completeness, the 444 has two of these carriages that look as though there's almost nothing underneath; marked as TOSL(A) and (B) IIRC.

An extra build of the 444 version would probably make a pretty useful 76 seater loco hauled coach, if a few were ever needed...

 

[David Goddard]

A different fleet I know, but if you look at a Cl458 the trailer coach has virtually nothing slung under it either.

 

[edwin_m]

The 380s are supplied as 3-car and 4-car versions so the car with virtually no equipment underneath will be the one that is missed out from the 3-car units.

 

[samuelmorris]

For completeness, the 444 has two of these carriages that look as though there's almost nothing underneath; marked as TOSL(A) and (B) IIRC.

An extra build of the 444 version would probably make a pretty useful 76 seater loco hauled coach, if a few were ever needed...

Yeah I think the 444 has to be the most pronounced example - due to the longer vehicles the empty space between the bogies is even longer.

 

[Des Iroman]

DMOSA/B- 4 motors (one on each axle, bogie mounted), Main compressor, brake equipment, Traction pack (converting the DC from the ACU's to AC for the motors), Sanders and air tanks.

Seems strange that the traction supply is fed from the ACUs - on a 350 the traction units (TCUs) are fed directly off the secondary transformer windings, as are the ACUs.

 

[The_Stig]

Seems strange that the traction supply is fed from the ACUs - on a 350 the traction units (TCUs) are fed directly off the secondary transformer windings, as are the ACUs.

Yeah, you are correct.

I started to think of how the 334 does it and got confused (although they are named differently).

I really should read my posts after writing them!

My apologies.