Mark 4 DVT Noise

[ryan125hst]

I watched this old video of an East Coast Intercity 225 the other night and noticed the strange sound the DVT produces. I know all the Mark 4 coaches have a static converter (which converts the 1000V AC Electric Train Supply to 400V AC three phase power for use by air conditioning, catering etc) which make a noticeable sound, but the sound from the DVT sounds different as it seems to vary in pitch a lot more than the other coaches. Is there a reason this is the case on the DVT's?

 

[TRAX]

This does sound like a static converter as well.

 

[ryan125hst]

I wonder if it is a slightly different static inverter to those used on passenger coaches? Or maybe it's starting to go faulty? I'm sure I've heard it before though that DVT's sound like this so I'd be interested to understand why.

 

[BillStampy]

I watched this old video of an East Coast Intercity 225 the other night and noticed the strange sound the DVT produces. I know all the Mark 4 coaches have a static converter (which converts the 1000V AC Electric Train Supply to 400V AC three phase power for use by air conditioning, catering etc) which make a noticeable sound, but the sound from the DVT sounds different as it seems to vary in pitch a lot more than the other coaches. Is there a reason this is the case on the DVT's?

It's probably a similar case to the coaches, TfW's DVTs do it too.

 

[boiledbeans2]

I'd like to jump on this thread and ask what's that "tick tick" sound, like a clock? I hear it on many older trains as well.

 

[43183]

I'd like to jump on this thread and ask what's that "tick tick" sound, like a clock? I hear it on many older trains as well.

probably the auto drain valves on the air tanks

 

[hexagon789]

I'd like to jump on this thread and ask what's that "tick tick" sound, like a clock? I hear it on many older trains as well.

Spirax valve - as mentioned in post #6, it allows water to drain from the air system.

 

[Elecman]

Condensate drain valves opening and closing

 

[boiledbeans2]

probably the auto drain valves on the air tanks

Spirax valve - as mentioned in post #6, it allows water to drain from the air system.

Condensate drain valves opening and closing

Thanks for your replies!

 

[ryan125hst]

What's the reason for the DVT's requiring a Spirax valve as they don't, to my knowledge, contain an air compressor?

 

[ryan125hst]

Just had a thought - is it anything to do with the E70 brake valve used to ensure the air brakes apply from both ends at the same time?

 

[43096]

Just had a thought - is it anything to do with the E70 brake valve used to ensure the air brakes apply from both ends at the same time?

DVTs have DW3s don’t they?

 

[D365]

DVTs have DW3s don’t they?

Good question. I was about to cite traintesting.com, but it appear that this is referring to Class 43 ’DVTs’, as opposed to purpose built Mk3 or Mk4 DVTs:

Once the loco's early teething troubles were overcome during the running with the Mk2 stock, testing was extended to include a 5-car rake of Mk3 sleepers which could be run in push-pull mode with the HST DVT by use of a screened cable running the length of the train. This was most important with respect to the train's braking as the control system released and applied the brake from the 91 and the DVT. Hence when being hauled by the 91 the E70 brake valve in the DVT was held off by the TDM and any break in circuit (or a fault) meant a remote brake application from the DVT.

Previous posts on RailUK seem to state that all DVTs are fitted with DW3, as per Class 90. But my understanding was that the Class 91s are fitted with DW2?

 

[ryan125hst]

DVTs have DW3s don’t they?

I don't know, I've seen E70 mentioned before. Were they only fitted to HST's?

Previous posts on RailUK seem to state that all DVTs are fitted with DW3, as per Class 90. But my understanding was that the Class 91s are fitted with DW2?

But your quote mentions an E70 valve in the DVT?

 

[D365]

But your quote mentions an E70 valve in the DVT?

Dave wasn’t entirely clear in the writing of his article. The DVT in that instance was actually a buffered Class 43, which is what I had attempted to clarify in my writing.

Class 43 and Class 56 were the two locomotive/vehicle types which were fitted. Also to clarify that my BR training notes name the Davies & Metcalfe E70 as an entire ”brake control system”, not just a singular valve.

DW2, as fitted to Class 91, is the Westinghouse equivalent of the E70. The DW2 and E70 Brake Control Units are purportedly interchangeable.

However it’s the Westinghouse DW3 which is an entirely different system, hence my earlier question whether or not they are fitted to Mk4 DVTs. The Class 90s are the only vehicle I 100% know are fitted with DW3.

 

[s491]

Dave wasn’t entirely clear in the writing of his article. The DVT in that instance was actually a buffered Class 43, which is what I had attempted to clarify in my writing.

Class 43 and Class 56 were the two locomotive/vehicle types which were fitted. Also to clarify that my BR training notes name the Davies & Metcalfe E70 as an entire ”brake control system”, not just a singular valve.

DW2, as fitted to Class 91, is the Westinghouse equivalent of the E70. The DW2 and E70 Brake Control Units are purportedly interchangeable.

However it’s the Westinghouse DW3 which is an entirely different system, hence my earlier question whether or not they are fitted to Mk4 DVTs. The Class 90s are the only vehicle I 100% know are fitted with DW3.

Don't think that's entirely correct.

AFAIAA, 91's were all D+M brakes and had a version of the E70 which allowed blending of the brakes (rheostatic and air). The Mk4 DVT's were DW3's and Westinghouse brakes.

HST Power cars had a mix of E70 and DW2 - and as far as I know the only UK application of the DW2. 43002-152 were built with E70 brake control unit and 43153-198 built with DW2. As with cooler groups, the brake control units got mixed around with them appearing on power cars across all sectors. However once the re-power project had finished, all the DW2 units were with FGW/GWR. DW2's used to be instantly recognisable back in the day by whistling loudly when the brakes were applied through each brake step. This eventually disappeared when a choke was fitted on the unit exhaust.

 

[whoosh]

Some HSTs were fitted with a DW2 brake control unit instead of an E70. They were louder.

 

[ryan125hst]

DW2, as fitted to Class 91, is the Westinghouse equivalent of the E70. The DW2 and E70 Brake Control Units are purportedly interchangeable.

This is probably why I've never heard of the DW2 or DW3 until now - I guess everyone has just called them E70's.

Don't think that's entirely correct.

AFAIAA, 91's were all D+M brakes and had a version of the E70 which allowed blending of the brakes (rheostatic and air). The Mk4 DVT's were DW3's and Westinghouse brakes.

HST Power cars had a mix of E70 and DW2 - and as far as I know the only UK application of the DW2. 43002-152 were built with E70 brake control unit and 43153-198 built with DW2. As with cooler groups, the brake control units got mixed around with them appearing on power cars across all sectors. However once the re-power project had finished, all the DW2 units were with FGW/GWR.

I didn't realise the HST's had two different types. Was there a reason for this?

DW2's used to be instantly recognisable back in the day by whistling loudly when the brakes were applied through each brake step. This eventually disappeared when a choke was fitted on the unit exhaust.

Are there any videos of this, or was it only audible inside the power car?

 

[D365]

This is probably why I've never heard of the DW2 or DW3 until now - I guess everyone has just called them E70's.

That’s definitely not the case within the rolling stock industry.

I didn't realise the HST's had two different types. Was there a reason for this?

As I’m told the E70 and DW2 are functionally compatible, I can only assume dual sourcing. Similar to how the Class 15x classes had a mix of Davies & Metcalfe or Westinghouse brake controllers, but are compatible for multiple working.

 

[43096]

I didn't realise the HST's had two different types. Was there a reason for this?

BR’s dual sourcing policy, that also gave two types of HST cooler group (Marston and Serck) and two types of HST traction motor (Brush and GEC).