Class 442 Retractioning - What gets replaced?

[SpacePhoenix]

http://www.semgonline.com/gallery/class442_3.html

The top two photos there show the underframe of the motor coach of a 442, when the 442s get re-tractioned, will literally everything bolted to the underframe between the bogies get replaced (in addition to the traction motors)?

 

[swt_passenger]

Yes. I can't really think of any common components between that 1960s DC system and a 2017 AC traction system.

But they may distribute the motors further along the train anyway. Having everything except the pickup shoes fitted to one coach of 5 isn't exactly the modern way of doing things.

 

[cjmillsnun]

Yes. I can't really think of any common components between that 1960s DC system and a 2017 AC traction system.

But they may distribute the motors further along the train anyway. Having everything except the pickup shoes fitted to one coach of 5 isn't exactly the modern way of doing things.

I doubt the trailer coaches will be modified to carry heavier motor bogies.

Some of the underframe equipment on the DMC will be fore the HVAC and will likely remain.

 

[AM9]

The setup of 1600hp DC traction and airconditioning under the floor of even a 23m coach was something of a shoehorn exercise. DC motors are (for like power) heavier, larger and need more cooling than modern 3 phase ac motors. A full camshaft/resistor set rated for that power with weak field loads also hits both the space and heat buttons compared to modern sold-state inverters. Regen braking would be able to operate at much lower speeds so resistor banks could be designed for less frequent use.
Even rail standard air conditioning is more compact, has much lower refrigerant volumes and probably runs at higher pressure on more environmentally friendly refigerants, so the weight of the equipment on the MBLS could be much less than as originally built. I would assume that updated hotel supplies would be located on one or more of the trailers, (not sure where they are at the moment) - fed from the 750VDC bus.

 

[SpacePhoenix]

Would a lot of the cab controls need replacing to work with the new traction package?

Could extra guard's panels be installed whilst they're having the re-tractioning done to give guards more flexibility when dispatching?

Is the current air con system more like what was originally on the 159s?

 

[HarleyDavidson]

Would a lot of the cab controls need replacing to work with the new traction package?

Could extra guard's panels be installed whilst they're having the re-tractioning done to give guards more flexibility when dispatching?

Is the current air con system more like what was originally on the 159s?

Not necessarily, the joke called the Vossloh/Keipe AC traction system on a 455 uses the original controls that have been there from day 1.

What AM9 has failed to say is that a 442 has two sets of camshafts, one for shunt & series, the other for parallel & weak fielding. Also you can isolate one set of motors whilst keeping the others in should a fault arise (although I don't know if SN took that feature out).

I don't know if they'll keep the braking the same or they'll change it over to more modern stuff, like regenerative one's which TBQH are terrible at doing the change or blending from regen to disc. Likewise for traction systems, all the modern one's I've come across have a fundamental & fatal flaw in that they can't deal with snow & ice, whereas a good old camshaft can.

 

[AM9]

... What AM9 has failed to say is that a 442 has two sets of camshafts, one for shunt & series, the other for parallel & weak fielding. Also you can isolate one set of motors whilst keeping the others in should a fault arise (although I don't know if SN took that feature out).

I didn't 'fail to say it' as I didn't know that the 442s had separate S-P gear. I presume that a modern 3 phase ac system will have separate drives to each motor allowing one or more to be disabled if necessary.

I don't know if they'll keep the braking the same or they'll change it over to more modern stuff, like regenerative one's which TBQH are terrible at doing the change or blending from regen to disc. Likewise for traction systems, all the modern one's I've come across have a fundamental & fatal flaw in that they can't deal with snow & ice, whereas a good old camshaft can.

Surely if an ac traction system was added, the existing starting resistances would be unnecessary and any banks used for braking would need to be capable of the the regen. ac frequency range determined by the motors' spin speeds. Clearly the performance of the regen/discs blending is critical but the control technology is mature now and shouldn't result in traction that suffers worse than straight camshaft resistor stepping in poor adhesion conditions. Indeed, with the tight load angle control that three phase drives should have, wheelslip should be controllable per axle.
Once the decision to refit with an ac system has been made, the pressures on low maintenance and energy saving should demand regen, particularly on a heavily traffic route like the Portsmouth Direct.

 

[507 001]

I didn't 'fail to say it' as I didn't know that the 442s had separate S-P gear. I presume that a modern 3 phase ac system will have separate drives to each motor allowing one or more to be disabled if necessary.



Surely if an ac traction system was added, the existing starting resistances would be unnecessary and any banks used for braking would need to be capable of the the regen. ac frequency range determined by the motors' spin speeds. Clearly the performance of the regen/discs blending is critical but the control technology is mature now and shouldn't result in traction that suffers worse than straight camshaft resistor stepping in poor adhesion conditions. Indeed, with the tight load angle control that three phase drives should have, wheelslip should be controllable per axle.
Once the decision to refit with an ac system has been made, the pressures on low maintenance and energy saving should demand regen, particularly on a heavily traffic route like the Portsmouth Direct.

I think part of the problem re. Solid state vs. Camshaft control is that in periods of poor adhesion a camshaft controlled unit can be 'hand notched', in other words taking each resistance out one at a time, giving the driver a huge amount of control over the train. Modern solid state drives (when fitted to units being re-tractioned in particular) tend to have only 4 notches.....

 

[dp21]

http://www.semgonline.com/gallery/class442_3.html

The top two photos there show the underframe of the motor coach of a 442, when the 442s get re-tractioned, will literally everything bolted to the underframe between the bogies get replaced (in addition to the traction motors)?

I believe it will be a similar scope to the 321/442 projects. If VK/KE get the full refresh project, they were talking about taking these things back to bare metal so regardless of who does it, when First say "refurbished as new" it'll be closer to a renatus-style rebuild than just a retraction and a lick of paint.

I believe the idea will be to keep the skirts where possible however I think you're right in that whatever needs binning gets binned but things which can remain will remain but relocated.

 

[swt_passenger]

I believe it will be a similar scope to the 321/442 projects.

Was that supposed to be 455?

 

[dp21]

Was that supposed to be 455?

Apologies, yes.

 

[AM9]

I think part of the problem re. Solid state vs. Camshaft control is that in periods of poor adhesion a camshaft controlled unit can be 'hand notched', in other words taking each resistance out one at a time, giving the driver a huge amount of control over the train. Modern solid state drives (when fitted to units being re-tractioned in particular) tend to have only 4 notches.....

I presume that 'four notches' is the driver's controller positions rather than the granularity of incremental steps that the actual motor drives have. Does each motor have its own control loop that can take wheelslip correcting action or are they all fed from the same variable frequency ac which results in load angles potentially being different for any slipping wheels?

 

[Turboftg]

Will they lose their distinctive sound? https://youtu.be/_YPy3Vl810M?t=34m21s

 

[cjmillsnun]

Will they lose their distinctive sound? https://youtu.be/_YPy3Vl810M?t=34m21s

If the compressors are replaced yes

 

[SpacePhoenix]

If the compressors are replaced yes

Would the compressors have come from the REPs or would they have been new when the 442s were built?

 

[Mordac]

Do we know the dates for the (re)introduction of the 442s?

 

[MatthewRead]

Do we know the dates for the (re)introduction of the 442s?

Sometime in 2018.

 

[edwin_m]

I presume that 'four notches' is the driver's controller positions rather than the granularity of incremental steps that the actual motor drives have. Does each motor have its own control loop that can take wheelslip correcting action or are they all fed from the same variable frequency ac which results in load angles potentially being different for any slipping wheels?

I don't claim to know the answer to this but it's worth noting that an AC motor driven by a VVVF inverter has an even steeper traction characteristic than a series-wound DC motor. This means that actual motor speed increases above the demanded speed the motor torque drops away very quickly so it should decelerate back to close to the demanded speed before very long. It's still possible for all the wheels to "let go", but the electronics ought to be able to detect that the train is accelerating much faster than the laws of physics allow and reduce demanded speed/acceleration accordingly. Particular traction package designs may be better or worse at achieving this than others.

Worth noting also that manual notching has its place but it may not be possible to remain in an intermediate manual notch indefinitely because of the amount of heat being dissipated in the resistors at notches other than full series or full parallel.

 

[cjmillsnun]

Would the compressors have come from the REPs or would they have been new when the 442s were built?

From the sound of them, they are a piston in cylinder type compressor and could well have come from the REPs. However I don't know for certain.

 

[HarleyDavidson]

I don't claim to know the answer to this but it's worth noting that an AC motor driven by a VVVF inverter has an even steeper traction characteristic than a series-wound DC motor. This means that actual motor speed increases above the demanded speed the motor torque drops away very quickly so it should decelerate back to close to the demanded speed before very long. It's still possible for all the wheels to "let go", but the electronics ought to be able to detect that the train is accelerating much faster than the laws of physics allow and reduce demanded speed/acceleration accordingly. Particular traction package designs may be better or worse at achieving this than others.

Worth noting also that manual notching has its place but it may not be possible to remain in an intermediate manual notch indefinitely because of the amount of heat being dissipated in the resistors at notches other than full series or full parallel.

Well let's hope that the stuff the put under the 442s is Vossloh/Kiepe stuff because the traction control is non existent on the 455s which just spin hopelessly in damp/low adhesion conditions. I can knock a retractioned one out of the ball park if I had a camshaft unit which you can use a great deal of subtlety with.

 

[swt_passenger]

Well let's hope that the stuff the put under the 442s is Vossloh/Kiepe stuff because the traction control is non existent on the 455s which just spin hopelessly in damp/low adhesion conditions. I can knock a retractioned one out of the ball park if I had a camshaft unit which you can use a great deal of subtlety with.

I think you forgot the word NOT somewhere?

 

[HarleyDavidson]

I think you forget the word NOT somewhere?

Let's try that again...

Well let's hope that the stuff the put under the 442s is NOT Vossloh/Kiepe stuff because the traction control is non existent on the 455s which just spin hopelessly in damp/low adhesion conditions. I can knock a retractioned one out of the ball park if I had a camshaft unit which you can use a great deal of subtlety with.

 

[SpacePhoenix]

Did Siemens build all the traction equipment on the 444s? If they did, could some sort of variant be installed on the 442s?

 

[dp21]

Sometime in 2018.

Last I heard it was December 2018 but I can't add anything more than that.

Let's try that again...

Well let's hope that the stuff the put under the 442s is NOT Vossloh/Kiepe stuff because the traction control is non existent on the 455s which just spin hopelessly in damp/low adhesion conditions. I can knock a retractioned one out of the ball park if I had a camshaft unit which you can use a great deal of subtlety with.

I was of the understanding that Kiepe Electric had won the contract therefore I'm afraid your fears may be realised...

 

[Mordac]

Sometime in 2018.

Last I heard it was December 2018 but I can't add anything more than that.



I was of the understanding that Kiepe Electric had won the contract therefore I'm afraid your fears may be realised...

Thank you both.

 

[SpacePhoenix]

What's the max speed rating of the equipment that Vossloh/Kiepe have put on the 455s? If it's 100mph, then could identical equipment be put on the 442s, assuming that it's Vossloh/Kiepe that won the contract?

 

[MatthewRead]

Last I heard it was December 2018 but I can't add anything more than that.



I was of the understanding that Kiepe Electric had won the contract therefore I'm afraid your fears may be realised...

Hope it will be a little earlier than December 2018

 

[edwin_m]

What's the max speed rating of the equipment that Vossloh/Kiepe have put on the 455s? If it's 100mph, then could identical equipment be put on the 442s, assuming that it's Vossloh/Kiepe that won the contract?

I asked this a few weeks back, probably somewhere further back on this thread, and someone answered that the existing motors are different. So as a minimum the new motor would have to be different, which probably means different control gear as well.

 

[AM9]

I asked this a few weeks back, probably somewhere further back on this thread, and someone answered that the existing motors are different. So as a minimum the new motor would have to be different, which probably means different control gear as well.

The existing DC motors are EE546 which are 300Kw (400hp), whereas the standard for DC EMUs is the EE507 and its derivitives rated from about 200hp up to just over 300hp but on stock designed for SR routes, typically 250hp.
Thus the replacement ac motors would need to be of higher rating than the type retrofitted to the class 455s. Any increase in maximum power output would probably need to be moderated to prevent overloading the inadequate 3rd rail power supply system by the electronic control as is the case for Electrostars running on DC and the DC-only Desiros.
I would expect the power and control electronics to be of current design but capable of higher continuous power than the class 355s. The maximum running speed would of course be determined wheel diameter and gearing, - there not being the need to uprate the motors in service as was done for the LM class 350 110mph programme. Modern ac motors are more compact and power efficient than DC designs of the same power so accomodating them and their cooling equipment within the existing bogie space should not be an issue.
Just my views on the task.

 

[43096]

What's the max speed rating of the equipment that Vossloh/Kiepe have put on the 455s? If it's 100mph, then could identical equipment be put on the 442s, assuming that it's Vossloh/Kiepe that won the contract?

Speed depends on the gearing, surely.