175 retarder/hydrodynamic brake system

[Philip]

Has the retarder hydro brake in the class 175s and 180s been completely removed from the system, or is it just isolated and so potentially could it be brought back in use?

I haven't been on 180s for a long time so I'm just assuming they still only use friction and air brakes?

 

[Tynwald]

The hydrodynamic brake is built into the voith transmission, so hence it would never be removed. It has simply been isolated.

 

[superkev]

Perhaps someone can refresh my memory as to why the Voith 3 speed transmission hydrodynamic brake (retarder) on the 175's and 180's was isolated. Is it the same transmission on the 185's?
I believe it worked by using the various fluid couplings and torque convertors to to transfer energy to the transmission fluid and oil cooler.
I dont think the earlier 2 speed Voith unit used on the 15x 16x units or for that matter the new 6 speed ZF unit as used in the 172's and 195's incorporate a retarder.
For interest both current Voith and ZF bus and coach transmissions incorporate retarders.
K

 

[hexagon789]

Perhaps someone can refresh my memory as to why the Voith 3 speed transmission hydrodynamic brake (retarder) on the 175's and 180's was isolated. Is it the same transmission on the 185's?
I believe it worked by using the various fluid couplings and torque convertors to to transfer energy to the transmission fluid and oil cooler.
I dont think the earlier 2 speed Voith unit used on the 15x 16x units or for that matter the new 6 speed ZF unit as used in the 172's and 195's incorporate a retarder.
For interest both current Voith and ZF bus and coach transmissions incorporate retarders.
K

I believe 180s and 185s share transmissions, 175s I thought were two-speed?

Also, I thought 195s did have a retarder - a few YouTube videos certainly make it sound like they have one when they slow down.

 

[Philip]

For clarity is the system still isolated on all 175s and 180s?

I read that with 175s it was initially isolated not long after they entered passenger service because of overheating leading to the TMS shutting the engine down, but was reactivated some time later following repairs.

 

[Eccles1983]

It is not operational on 175's.

It causes too many issues, and an easy fix was to kill it. The brakes work well without it.

 

[O L Leigh]

Sprinters, among others, have Voith T211r transmissions. When we discussed this about 10 years ago it was mentioned that these have retarders or at least the capability for retarders. Either they were fitted and never used or they were capable of being fitted. I presume this wasn’t taken advantage of for the sake of simplicity.

 

[wobman]

For clarity is the system still isolated on all 175s and 180s?

I read that with 175s it was initially isolated not long after they entered passenger service because of overheating leading to the TMS shutting the engine down, but was reactivated some time later following repairs.

I know the brakes on 175's when they entered service were amazing compared to sprinters, then the hydrodynamic brakes were isolated and split disks fitted and now the brakes are ok.
There was a lot of overheating issues with the 175's due to the brakes, it was a shame as the brakes were much better with it reinstated.

 

[Philip]

In 175s the engine used to rev to what sounding like maximum revs when it was applied, any reason for this?

Also it was often the case that it would be working in one coach but not in another.

 

[Tynwald]

The 175 are fitted with voith T211HBR and the 180 T312HBR. The HBR stands for hydrodynamic brake. They were isolated for various issues, but the main one is the cost of maintaining was not justified for the relatively small saving in brake pad costs. Brake performance is not affected at all.
In HBR braking, the engine revs to increase the coolant pump speed, and thus increase the coolant flow through the voith oil cooler.

 

[Philip]

Thanks for the information.

 

[craigybagel]

To answer and to add to previous comments:

It's only a 2 speed transmission on a 175.
There's a particular MCB in a particular cupboard in each car that is kept permanent tripped which isolates the hydrodynamic brake - although there may have been extra steps taken to ensure the isolation is more permanent.
Even with it isolated, the disk brakes working alone on a 175 are still superior to the brakes on the rest of the fleet.

 

[Philip]

Thanks again. Does anyone know the status of the system on the 180s? I heard it was isolated on all of them many years ago and I couldn't hear it when Northern were operating them, but haven't been on one for a long time.

 

[hexagon789]

Thanks again. Does anyone know the status of the system on the 180s? I heard it was isolated on all of them many years ago and I couldn't hear it when Northern were operating them, but haven't been on one for a long time.

I assume still isolated as the original brake pads were changed for a different type because they wore too quickly.

I believe 185s do have functioning retarders, at least that's the impression i got.

 

[43096]

I assume still isolated as the original brake pads were changed for a different type because they wore too quickly.

If I remember correctly, when the hydrodynamic brake was isolated the 180s got the same brake pads as used on Eurostars and the 175s got the type used on the 180s.

 

[8J]

I assume still isolated as the original brake pads were changed for a different type because they wore too quickly.

I believe 185s do have functioning retarders, at least that's the impression i got.

Yes the hydro-dynamic brake on a 185 is still utilised and it is pretty rare to come across one that has the hydro-dynamic brake isolated.

I imagine the sheer weight of them means that they'd fly through brake pads if it were to be isolated.

 

[Hairy Bear]

Thanks again. Does anyone know the status of the system on the 180s? I heard it was isolated on all of them many years ago and I couldn't hear it when Northern were operating them, but haven't been on one for a long time.

Emr ones are all isolated. They were intending to reinstate them, but Hull Trains said...." you really don't wanna do that !".

 

[Tynwald]

One of the weak areas of the coradia units is the cooler groups. 185 have much better cooler groups from a different supplier. The coradia cooler groups realy struggle with the amount of heat generated in dynamic brake.

 

[Philip]

I have read that in the past both Coradia and Desiro hd brakes were often isolated temporarily during leaf-fall season.

Interesting reading about how each coach has a trip for the system in 175s, this explains why you could hear it in one coach but not the other. Even when it was in use on 175s it seemed temporamental back then because you'd hear it on a particular unit at one point, then later isolated and then back in use again.

 

[edwin_m]

Even when it was in use on 175s it seemed temporamental back then because you'd hear it on a particular unit at one point, then later isolated and then back in use again.

Perhaps some kind of cutout if the fluid got too hot?