Differential Speed Restrictions

[swisstrains]

I'll second Shed Cat's comments. Thanks Les, your explanations go a long way towards explaining matters.
To go back to my original TSR query, I am now starting to think that the two light engines that I saw going "noticeably slower" than the passenger trains were doing so for completely different reasons. Today I saw a light engine pass through the TSR much faster than the other two and certainly way above the speed that freights do.
Your mention of light engine speed limits does, however, bring one question to mind....... Would a consist of say 5 locos coupled together still be subject to the same conditions as a single light engine?

[LesG]

Would a consist of say 5 locos coupled together still be subject to the same conditions as a single light engine?[/QUOTE]

Depends as to why 5 loco are coupled are they,

1. in multy
2. in tandem

To explain if loco's are in multy that means the loco are all coupled up electrically and can be controlled by 1 driver getting power from all locos.

Or in tandem is the locos are not coupled electrically, can be worked by 1 driver but power from the lead loco only.

To try and answer the querie, I think providing all the locos are in good working order with no brake problems etc then yes I believe that 5 light locos are classed the same as 1 but I will find out and get back soon.

Les

[swisstrains]

Les,
I assume that the consists I am thinking of are not running in multiple because they are often mixtures of 66's and 60's. I don't think 60's and 66's can multiple together, can they?
It is nearly always on a Saturday afternoon when I see them so I assume that they are travelling from the EWS depot at Warrington to Crewe ready for PW duties on the Sunday.

[LesG]

Originally Posted by swisstrains

Les,
I assume that the consists I am thinking of are not running in multiple because they are often mixtures of 66's and 60's. I don't think 60's and 66's can multiple together, can they?
It is nearly always on a Saturday afternoon when I see them so I assume that they are travelling from the EWS depot at Warrington to Crewe ready for PW duties on the Sunday.

Your spot on a 66 can only multi up with another 66/67 or a 59.

Les

[wessexrailwaysdude]

kinda confusing....just as you think theres a simple explination theres another explination to go with it that raises more questions! Certainly a complicated subject!

[wessexrailwaysdude]

locomotives working in multiple are down to the connectors linking each locomotive not the coupling of the trains.

so if a class 60 was attached to a class 66 they wouldn't be able to work in multiple, one of the locomotives would be "dead" or running idle if the engine was running.

Class 59's Class 66's and class 67's can work together in powering trains as they use a system called AAR or something like that its called.

But going back to speed restrictions. The class 66 differs from the class 59 in the sense that the wheels follow the curvature of the track as the end wheels of each boogie are self steering thus preventing rail wear so would be interesting to know if there is a difference for class 66 on speed restictions if it goes on wear and tear on some things.

Plus class 59's (not sure about the 59'2's tho) have some sort of computer control thing that controls the amount of wheel slip on the rail...allowing the wheels to slip by a certain amount on pulling away from a heavy start but the amount they are allowed to slip by is small.

but would be interesting to know if things like that affect speed restrictions on loco's.

[LesG]

Originally Posted by wessexrailwaysdude

locomotives working in multiple are down to the connectors linking each locomotive not the coupling of the trains.

so if a class 60 was attached to a class 66 they wouldn't be able to work in multiple, one of the locomotives would be "dead" or running idle if the engine was running.

Class 59's Class 66's and class 67's can work together in powering trains as they use a system called AAR or something like that its called.

But going back to speed restrictions. The class 66 differs from the class 59 in the sense that the wheels follow the curvature of the track as the end wheels of each boogie are self steering thus preventing rail wear so would be interesting to know if there is a difference for class 66 on speed restictions if it goes on wear and tear on some things.

Plus class 59's (not sure about the 59'2's tho) have some sort of computer control thing that controls the amount of wheel slip on the rail...allowing the wheels to slip by a certain amount on pulling away from a heavy start but the amount they are allowed to slip by is small.

but would be interesting to know if things like that affect speed restrictions on loco's.

The simple answer is NO to the different class of loco on speed restrictions, a differential speed restriction applies to the class of train not the loco.

As for the 59/2, Yes they have a system on them called creep control this basically works similar to the 66/67 in that when the computer detects the wheel starting to slip (not slide) then the system will automatically start to apply sand to the rails, this is what you see when a 59/66 or a 67 is pulling away and you see a dust trail from the leading bogie. The system will cut out in normal conditions at about 10mph unless the computer detects poor rail conditions by continuos wheel slip.
In the case of a train sliding then the sand has to be applied manually by the conrol lever in the cab by the driver.

To explain slid/slip, Wheel slip occurs under power when pulling away etc and wheel slide occurs usually under braking conditions.

Hope this clears a few thing up.

Les

[Foghut]

Ok Les, here's some questions for you. (I don't know the first thing about locos, as I only ever drive EMUs).

1) If a loco like a 66 is dead and all the air has leaked out of the main res and brake cylinders, does it have a spring operated safety brake, or will it run away if you haven't applied a handbrake ?

2) If you are in tandem with another 66 (so that presumably you're effectively hauling it dead), do you have to isolate the brakes on the other unit, or what do you do ?

TIA

Foggy

[LesG]

Originally Posted by Foghut

Ok Les, here's some questions for you. (I don't know the first thing about locos, as I only ever drive EMUs).

1) If a loco like a 66 is dead and all the air has leaked out of the main res and brake cylinders, does it have a spring operated safety brake, or will it run away if you haven't applied a handbrake ?

2) If you are in tandem with another 66 (so that presumably you're effectively hauling it dead), do you have to isolate the brakes on the other unit, or what do you do ?

TIA

Foggy

Simple answer to point one is yes it will run away if the parking brake is not applied and/or scotched.

Point two is yes we isolate the brake unit, also known as the E70, from inside the clean air air compartment, What this does, in laymans terms is it stops the brake pipe control on the DIT loco but allows the brakes to apply when operated from the lead loco.

It gets a bit more complicated if the loco is a failure and gets assistance from the rear, We have to isolate the E70 and the AFT cock (assistance to failed trains) which allows us to move the train with the failed loco dead therefore unable to maintain 72.5psi in the brake pipe, used only to clear the line so that a working loco can be put on the front of the train.

Not forgetting that a brake test MUST be carried out after attaching a loco to the failed train.

Hope you can understand that basic explanation, its harder to explain than do.

Les

[Foghut]

Originally Posted by LesG

Hope you can understand that basic explanation, its harder to explain than do.

Les

Like most things on the railway.

And thanks for the clear and concise explanation Les