334 pretending to be a steam loco

[Bittern]

Well, almost.

334036 operated a Milngavie - Lanark service (actually, she would still be on her way to Lanark now). Every time the breaks were applied, the unit let off a hissing sound reminiscent of a steam locomotive. The ride also felt quit jerky. This is the first time I've ever heard a 334 acting this way.

 

[asylumxl]

334s have air brakes do they not?

 

[O L Leigh]

That would have been the WSP acting to prevent a slide. Clearly the rail conditions were far from ideal.

O L Leigh

 

[Bittern]

It was slightly wet, but no more than usual.

 

[O L Leigh]

Even so, that is classic WSP activity. Perhaps the unit had a fault or it was set too sensitive, but the description you have given points to that and that alone.

O L Leigh

 

[Goldfish62]

Even so, that is classic WSP activity. Perhaps the unit had a fault or it was set too sensitive, but the description you have given points to that and that alone.

O L Leigh

It must be a Juniper trait as the WSP equipment on the 458s is extremely sensitive in even the slightest damp conditions. It leads to a very jerky ride. Despite the sensitive WSP 458s have suffered from very heavy wheelflats in the past, but this seems to have been resolved.

 

[466.networkers]

The Class 466s have been like this in the recent damp conditions - shuddering to a halt and the brakes/WSP stuggling to find grip - at least with the wheelslip the traction motors make some wonderful weird sounds!

 

[The_Stig]

What coach were you sitting in?

 

[Bittern]

I was at the front of the unit.

 

[The_Stig]

I was at the front of the unit.

Ah, I was thinking maybe the pantograph coach was another possibility as the air dryer often dumps air and has a similar sound you described.

 

[rail-britain]

the pantograph coach the air dryer often dumps air

I never knew EMUs had "air dryers"
What is the purpose of that?
Take air from the system, then dump it?

 

[driver9000]

I never knew EMUs had "air dryers"
What is the purpose of that?
Take air from the system, then dump it?

All compressed air systems have a dryer, it's purpose is to remove moisture from the drawn in air before it is passed to the tank and pipe work. The 'clicking' sound sometimes heard coming from locos and units is the moisture being released.

 

[The_Stig]

All compressed air systems have a dryer, it's purpose is to remove moisture from the drawn in air before it is passed to the tank and pipe work. The 'clicking' sound sometimes heard coming from locos and units is the moisture being released.

Not all units have them, 314's, 318's, 322's don't have them. They have valves on their main air tanks that blow off giving the clicking sound. These units have a system that dispenses a type of anti-freeze into the air system to stop any moisture that hasn't been expelled freezing.

 

[rail-britain]

Not all units have them, 314's, 318's, 322's don't have them

I thought that was the case, the only blowers I was aware (on Scottish EMUs) are the Class 334 and 380
I also assume the Class 320 doesn't have them

Hence why the Class 334 had issues with the snow, as they "sucked" the snow up; I can see this being a similar issue with the Class 380, which might also explain why the Class 314 units have been retained (crystal ball moment)

 

[The_Stig]

I thought that was the case, the only blowers I was aware (on Scottish EMUs) are the Class 334 and 380
I also assume the Class 320 doesn't have them

320's do currently have air dryers although they are being phased out. They are receiving the same 'anti-freeze' units that are fitted to 318's. This is due to the big freeze last year and issues with their air dryers.

Hence why the Class 334 had issues with the snow, as they "sucked" the snow up; I can see this being a similar issue with the Class 380, which might also explain why the Class 314 units have been retained (crystal ball moment)

All the units suck air into their compressors, the air dryer simply removes the water.

I think you mean the 334's having forced air cooling? This allowed snow to be pulled through some of the electronics?

 

[route101]

The class 334s do have a worse ride than the 318s . Very jerky.