Questions about driving trains.

[notadriver]

I would like to start this thread for anyone who has any questions about the art of actual train driving. There are a number of resident train drivers active on this forum including myself so if I (we) can answer questions I (we) will

 

[455driver]

I would like to start this thread for anyone who has any questions about the art of actual train driving. There are a number of resident train drivers active on this forum including myself so if I (we) can answer questions I (we) will unless some know all with a train sim game beats us to it!

Corrected that for you!

How many of the answers are going to be-

Its down to the drivers route knowledge.

 

[telstarbox]

On the basis that 'there's no such thing as a stupid answer':

In a car the main controls are the steering wheel (controls direction), gearbox, pedals (control speed) and the handbrake (keeps the car still). What are the main controls in a train?

 

[notadriver]

It's a valid question. It will be the power controller and the brake controller. On multiple units they maybe combined. But there are other additional controls which are needed to maintain progress (the drivers safety device and the AWS acknowledge button ) and I can't think of a car equivalent for these things.

 

[Eagle]

Here's one that I feel I should know but don't: is the power control lever a continuous range (like the accelerator in a car) or does it have a series of steps/gears?

 

[Trainfan344]

Go on then, how realistic would you as a driver rate a simulation game such as train simulator? What are the key differences between driving a train from your laptop or computer in your living room to sitting in the cab of an actual train and driving it?

 

[notadriver]

Here's one that I feel I should know but don't: is the power control lever a continuous range (like the accelerator in a car) or does it have a series of steps/gears?

It depends on the traction of course. Electric multiple units tend to have 4 power notches or steps. Each step is approximately 25% up to 100 % on modern multiple units. (1990 onwards). Diesel multiple units have more power notches - 7 tends to be the usual.

Locomotives often have a continuous range.

 

[notadriver]

Go on then, how realistic would you as a driver rate a simulation game such as train simulator? What are the key differences between driving a train from your laptop or computer in your living room to sitting in the cab of an actual train and driving it?

Well for me - apart from the obvious - that there is no feel, the real thing is 'bucks' about a bit more especially over point work, the sounds in the train sim for electrics are never quite right and the braking performance isn't like the real thing either (the emergency brake in a modern EMU is very good in my opinion)

 

[455driver]

Here's one that I feel I should know but don't: is the power control lever a continuous range (like the accelerator in a car) or does it have a series of steps/gears?

Depends on the traction, on the units I drive the 444/450 and 458s are continuous range (they do have notches but they can be ignored) but the older 455s just have 4 notches even though the mid notches are actually 8 steps.

A 455 power output is-
Off

Notch 1 (shunt) is each pair of traction motors in series (electricity goes through one motor, then the other motor, each motor effectively gets half the voltage before going to earth) this is series with all 8 resistances in circuit.

Notch 2 (series) the camshaft will remove each resistance out in turn until it is direct feed.

Notch 3 (parallel) is each pair of traction motors in parallel (the electricity is directed to both motors at the same time so they both receive the full voltage) with all 8 resistances back in circuit, the camshaft will again remove each resistance in turn until direct feed.

Notch 4 (weak field) is parallel with the magnetic voltage reduced to reduce the amount of back EMF generated by the motors, this means they can spin faster, no resistances in on this one it is one position direct feed.

When in 2 or 3 if the controller is placed back to 1 the camshaft will remain in that position and not run up and remove the resistances and the driver can notch up by going from 1 to 2 and back to 1, this will remove 1 resistance grid at a time and is used in poor railhead conditions because once the wheels start spinning the only thing the driver can do is go back to off and start again, you cannot go backwards on the camshaft, once its moved forward thats it.
The surging you can feel as the train pulls away is the resistances being removed. and is more noticeable at the lower speeds (in series).

 

[ryan125hst]

On the basis that 'there's no such thing as a stupid answer':

Don't you mean "there's no such thing as a stupid question"?

 

[455driver]

Depends on the traction, on the units I drive the 444/450 and 458s are continuous range (they do have notches but they can be ignored) but the older 455s just have 4 notches even though the mid notches are actually 8 steps.

A 455 power output is-
Off

Notch 1 (shunt) is each pair of traction motors in series (electricity goes through one motor, then the other motor, each motor effectively gets half the voltage before going to earth) this is series with all 8 resistances in circuit.

Notch 2 (series) the camshaft will remove each resistance out in turn until it is direct feed.

Notch 3 (parallel) is each pair of traction motors in parallel (the electricity is directed to both motors at the same time so they both receive the full voltage) with all 8 resistances back in circuit, the camshaft will again remove each resistance in turn until direct feed.

Notch 4 (weak field) is parallel with the magnetic voltage reduced to reduce the amount of back EMF generated by the motors, this means they can spin faster, no resistances in on this one it is one position direct feed.

Most times you just pull through into 4 fairly quickly (some drivers just yank it straight into 4 from a standing start), into 1 wait a second, into 2 wait a second,into 3 wait a second, unto about 10mph and into 4 and away, this means the camshaft will rotate as quickly as possible and feed the motors the maximum amount of electricity giving the fastest possible acceleration.

Also when in 2 or 3 if the controller is placed back to 1 the camshaft will remain in that position and not run up and remove the resistances and the driver can notch up by going from 1 to 2 and back to 1, this will remove 1 resistance grid at a time and is used in poor railhead conditions because once the wheels start spinning the only thing the driver can do is go back to off and start again, you cannot go backwards on the camshaft, once its moved forward thats it.
The surging you can feel as the train pulls away is the resistances being removed. and is more noticeable at the lower speeds (in series).

Edit-
On all the others I drive you can go back and forward to your hearts content which is not half as much 'fun' in poor railhead but does make wheelslip (spinning) control a lot easier.
--- old post above --- --- new post below ---

On the basis that 'there's no such thing as a stupid answer':

Oh there are trust me! dont you mean there is no such thing as a stupid question, that I would agree with.

Basically a reverser, a power handle and a brake handle. Thats the main 3 then there are the lights and all the switches, the circuit breakers, all the safety systems DSD, DVD, AWS, TPWS etc but realistically there isnt much needed to get a train moving.

 

[O L Leigh]

A 455 power output is-
Off

Notch 1 (shunt) is each pair of traction motors in series (electricity goes through one motor, then the other motor, each motor effectively gets half the voltage before going to earth) this is series with all 8 resistances in circuit.

Notch 2 (series) the camshaft will remove each resistance out in turn until it is direct feed.

Notch 3 (parallel) is each pair of traction motors in parallel (the electricity is directed to both motors at the same time so they both receive the full voltage) with all 8 resistances back in circuit, the camshaft will again remove each resistance in turn until direct feed.

Notch 4 (weak field) is parallel with the magnetic voltage reduced to reduce the amount of back EMF generated by the motors, this means they can spin faster, no resistances in on this one it is one position direct feed.

When in 2 or 3 if the controller is placed back to 1 the camshaft will remain in that position and not run up and remove the resistances and the driver can notch up by going from 1 to 2 and back to 1, this will remove 1 resistance grid at a time and is used in poor railhead conditions because once the wheels start spinning the only thing the driver can do is go back to off and start again, you cannot go backwards on the camshaft, once its moved forward thats it.
The surging you can feel as the train pulls away is the resistances being removed. and is more noticeable at the lower speeds (in series).

The same is broadly similar for 25kV AC EMUs of the BR era, even though the majority of these have thyristors rather than camshafts.

Notch 1 is a shunt notch giving around 5mph.
Notch 2 is half power which, on a Cl317, will give around 50-60mph. It's also a good notch for cruising and maintaining speed on the flat.
Notch 3 is full power.
Notch 4 is "weak field".

Newer units are a bit odder. Cl379s still have four power notches, but they don't correspond to the same pattern as older units. If you had a long enough run you could hit 100mph in notch 1. This was attempted during mileage accumulation. The train got up to about 80mph before the driver had to brake due to cautionary signal aspects. It could make coupling units a bit tricky to avoid a heavy contact.

O L Leigh

 

[cjp]

Which is easier to drive diesel or electric mutiple units and which do you prefer - simple or more challenging?

 

[455driver]

Newer units are a bit odder. Cl379s still have four power notches, but they don't correspond to the same pattern as older units. If you had a long enough run you could hit 100mph in notch 1. This was attempted during mileage accumulation. The train got up to about 80mph before the driver had to brake due to cautionary signal aspects. It could make coupling units a bit tricky to avoid a heavy contact.

O L Leigh

On them I think the notches control how quickly the power ramps up rather than limiting the actual power output, that trick was tried with a 458 with similar results.

 

[notadriver]

Looking on the traction status screen of ab electrostar from a standing start

Notch 4 : 132 kN total
Notch 2 : 66 kN total

These are from a 4 car unit so at least from a standing start it represents a percentage of power.

 

[455driver]

Looking on the traction status screen

Thats posh!

 

[O L Leigh]

Which is easier to drive diesel or electric mutiple units and which do you prefer - simple or more challenging?

It's a different technique, but there really isn't a lot of difference apart from that.

O L Leigh

 

[Whistler40145]

How difficult is it for a train driver who normally works freight trains with modern locomotives then retain traction knowledge & also work on heritage locomotives hauling Railtours where modern technology doesn't exist?

 

[notadriver]

I have a friend who does exactly that - he drives a first gen DMU for a hobby. The best example was in 'toughest place to be a train driver' where the Virgin train driver went to drive those old diesels on steeply graded routes overseas ?

 

[rebmcr]

Any chance of a cab ride?

 

[O L Leigh]

No.

O L Leigh

 

[fsmr]

I have a friend who does exactly that - he drives a first gen DMU for a hobby. The best example was in 'toughest place to be a train driver' where the Virgin train driver went to drive those old diesels on steeply graded routes overseas ?

Even better when you have to make your power source as well as drive it
I.e single handed firemans and driver steam on narrow gauge
Keeping a steamer running on poor coal on greasy rails can be a real test

You can see why the drivers that switched from steam to first gen type 1s and 2s in the 50s and 60s got so less stressed about the job.
Having said that it can be a real sense of achievement when it works

 

[455driver]

Any chance of a cab ride?

I cant even get my own kids a cab ride! :cry:

 

[notadriver]

I cant even get my own kids a cab ride! :cry:

Sure you can. Just ask your Driver Manager very nicely if he could arrange to come with you

 

[455driver]

Sure you can. Just ask your Driver Manager very nicely if he could arrange to come with you

No chance with my new DM, he still has the stamp or his arse from College, he is a complete ' but the Company Handbook says' type of person and has never driven a train!

 

[ryan125hst]

Depends on the traction, on the units I drive the 444/450 and 458s are continuous range (they do have notches but they can be ignored) but the older 455s just have 4 notches even though the mid notches are actually 8 steps.

A 455 power output is-
Off

Notch 1 (shunt) is each pair of traction motors in series (electricity goes through one motor, then the other motor, each motor effectively gets half the voltage before going to earth) this is series with all 8 resistances in circuit.

Notch 2 (series) the camshaft will remove each resistance out in turn until it is direct feed.

Notch 3 (parallel) is each pair of traction motors in parallel (the electricity is directed to both motors at the same time so they both receive the full voltage) with all 8 resistances back in circuit, the camshaft will again remove each resistance in turn until direct feed.

Notch 4 (weak field) is parallel with the magnetic voltage reduced to reduce the amount of back EMF generated by the motors, this means they can spin faster, no resistances in on this one it is one position direct feed.

When in 2 or 3 if the controller is placed back to 1 the camshaft will remain in that position and not run up and remove the resistances and the driver can notch up by going from 1 to 2 and back to 1, this will remove 1 resistance grid at a time and is used in poor railhead conditions because once the wheels start spinning the only thing the driver can do is go back to off and start again, you cannot go backwards on the camshaft, once its moved forward thats it.
The surging you can feel as the train pulls away is the resistances being removed. and is more noticeable at the lower speeds (in series).

Very interesting post, particularly when I am hoping to do an Engineering degree and even more so when, after attending a talk after a University open day, I am hoping to apply for an Electrical Engineering course!

I understand what you have written about series/parallel motors and resistances, but I don't understand weak field. How is it achieved?
--- old post above --- --- new post below ---

I cant even get my own kids a cab ride! :cry:

I'm surprised about that. There are a few videos on YouTube of a lad having a few cab rides (with a Driver Manager in attendance). Most of them were on South West Trains as well- he rode on a 444 and a 455 for certain. I think he got to ride on a 450, and he also got to ride on a Southern class 171.

 

[455driver]

I understand what you have written about series/parallel motors and resistances, but I don't understand weak field. How is it achieved?

When an electric motors commutator is spinning it will create Back EMF which works against the flow of incoming electricity, once the point of equilibrium is reached the commutator cannot rotate any faster but by reducing the voltage sent to the traction motor (electro)magnets, the lower field strength means the motor will produce less back EMF and the commutator can spin faster.
An electric motor needs full field strength to get going (maximum torque) but once spinning that maximum field strength will work against it when rotating at speed.

 

[rebmcr]

When an electric motors commutator is spinning it will create Back EMF which works against the flow of incoming electricity, once the point of equilibrium is reached the commutator cannot rotate any faster but by reducing the voltage sent to the traction motor (electro)magnets, the lower field strength means the motor will produce less back EMF and the commutator can spin faster.
An electric motor needs full field strength to get going (maximum torque) but once spinning that maximum field strength will work against it when rotating at speed.

Very interesting. Does that mean when driving a Class 86 or 87, you would actually dial back the taps to continue accelerating once you reach a decent speed?

 

[ryan125hst]

When an electric motors commutator is spinning it will create Back EMF which works against the flow of incoming electricity, once the point of equilibrium is reached the commutator cannot rotate any faster but by reducing the voltage sent to the traction motor (electro)magnets, the lower field strength means the motor will produce less back EMF and the commutator can spin faster.
An electric motor needs full field strength to get going (maximum torque) but once spinning that maximum field strength will work against it when rotating at speed.

I see. I've not heard of Back EMF before- you learn something new everday! So how is the voltage to the motors reduced? The 455's are DC trains and transformers don't work with direct current!

 

[455driver]

So how is the voltage to the motors reduced? The 455's are DC trains and transformers don't work with direct current!

Do you know I am not sure

Remember there are 2 seperate feeds to the traction motors, the normal 2 wires going to the brushes (as in a model loco) and 2 going to the magnets to creat the field (these are permanent magnets and so dont have a feed on models), these are the ones that are reduced to weaken the field.