Do trains have a clutch?

[Deafdoggie]

I have a very basic question, so apologies. I know some of you will laugh at this, but I really didn't know!

My youngest is learning to drive (a car!) but we were on a class 156 and as it pulled away it revved up nicely and he joked "the drivers got his right foot down, he's gentle on the clutch-we haven't stalled!" Now, obviously, we know that the driver doesn't really have pedals. But then we actually started getting a bit vague. Is there a "clutch"? Could you stall a train?? We've never known a train stall, but is it possible?

I know, we're stupid! But we just wondered on the stalling capabilities of a train. Be gentle on us for a basic question!

 

[azt]

There isn't a clutch, probably a fluid coupling or torque converter. you can get loads of info/pix on this if you do a google search.

Hope this helps

 

[driver9000]

No there isn't a clutch and you can't stall the engine in that way either. The 156 has a 2 stage transmission which is a torque converter up to 45mph when it changes to a fluid flywheel. You can hear the engine revs drop when it changes over.

There is a foot pedal called the DSD (Drivers Safety Device) which must be kept pressed when the train is moving.

 

[12LDA28C]

There isn't a clutch, probably a fluid coupling or torque converter. you can get loads of info/pix on this if you do a google search.

Hope this helps

There would be a fluid coupling and a torque converter. The torque converter handles acceleration from a stand up to a certain speed, then the fluid coupling comes into play after that.

 

[Purple Train]

Probably the best source for details of how it works is the Locomotive Ladybird book from 1968!

Although you've got me thinking now. There isn't a clutch on diesel-mechanical trains, is there?

 

[azt]

Didn't know that a fluid coupling and a torque converter could be used together. The experience I have is not on the railway, it's either been a fluid coupling or torque converter connected to the prime mover depending on the application.

 

[Mat17]

Although you've got me thinking now. There isn't a clutch on diesel-mechanical trains, is there?

I don't think so, happy to be proved wrong.

The first gen units did have a gear selector though in addition to the throttle. Whereas second gen units don't have a gear selector, I don't think. I don't know anything about modern trains, I've only ever been in the cabs of first gen units.

 

[weastebusdepot]

The first gen units did have a gear selector though in addition to the throttle. Whereas second gen units don't have a gear selector, I don't think. I don't know anything about modern trains, I've only ever been in the cabs of first gen units.

Yes, there was a British Transport Film shown on Talking Pictures TV not long ago which was a film on how to drive a first generation DMU. Lots of instruction on waiting for the revs to be at the right level before engaging the next gear to avoid damaging the gearbox.

 

[Enthusiast]

I can remember sitting in the front passenger seat behind the driver's cab of the early Craven DMUs which operated out of Kings Cross, watching the driver change gear (I think there were four). No clutch though.

 

[Ashley Hill]

Some mechanical shunters had gearboxes and clutches. On one I used to drive the gearbox resembled a small ground frame and the clutch was a pedal. The process of changing gear was sow slow that you lost momentum between gear changes.

 

[12LDA28C]

Probably the best source for details of how it works is the Locomotive Ladybird book from 1968!

Although you've got me thinking now. There isn't a clutch on diesel-mechanical trains, is there?

No clutch on DMMUs, no. The gears are changed by the means of 'brake bands' within the epicylic gearbox which basically perform the same function as a clutch.

 

[Deafdoggie]

I think we have established why I'm not a train driver! Amongst many ther reasons!

 

[ComUtoR]

A couple of EMU's I've driven would often 'fail to take power' if you didn't pull away properly and they would then start to roll away.

 

[hexagon789]

I have a very basic question, so apologies. I know some of you will laugh at this, but I really didn't know!

My youngest is learning to drive (a car!) but we were on a class 156 and as it pulled away it revved up nicely and he joked "the drivers got his right foot down, he's gentle on the clutch-we haven't stalled!" Now, obviously, we know that the driver doesn't really have pedals. But then we actually started getting a bit vague. Is there a "clutch"? Could you stall a train?? We've never known a train stall, but is it possible?

I know, we're stupid! But we just wondered on the stalling capabilities of a train. Be gentle on us for a basic question!

The engine is never directly connected to the wheels, so you can't stall it like a car.

No there isn't a clutch and you can't stall the engine in that way either. The 156 has a 2 stage transmission which is a torque converter up to 45mph when it changes to a fluid flywheel. You can hear the engine revs drop when it changes over.

There is a foot pedal called the DSD (Drivers Safety Device) which must be kept pressed when the train is moving.

Can be as low as 30mph in low power notches.

Probably the best source for details of how it works is the Locomotive Ladybird book from 1968!

Although you've got me thinking now. There isn't a clutch on diesel-mechanical trains, is there?

There is a sort of clutch 'idea' - intermediate gears being held by brakebands, but gear changes were semi-automatic on 1st gens, so no manual clutching anyway. Shut off power, count to 2, change gear (but the gearbox would do the actual change, driver is just selecting the gear), count to 2, re-open throttle.

I think we have established why I'm not a train driver! Amongst many ther reasons!

The Railcar website has good explanations of 1st generation DMU transmission with the four-speed epicyclic manual transmissions.

Locodocs has some BR manuals, including one for the Class 150 with a very in-depth explanation of the hydraulic transmission found on 15x Sprinters.

 

[QueensCurve]

I have a very basic question, so apologies. I know some of you will laugh at this, but I really didn't know!

My youngest is learning to drive (a car!) but we were on a class 156 and as it pulled away it revved up nicely and he joked "the drivers got his right foot down, he's gentle on the clutch-we haven't stalled!" Now, obviously, we know that the driver doesn't really have pedals. But then we actually started getting a bit vague. Is there a "clutch"? Could you stall a train?? We've never known a train stall, but is it possible?

I know, we're stupid! But we just wondered on the stalling capabilities of a train. Be gentle on us for a basic question!

May I request that those with a question, however basic, put it in the subject line.