Brake force of a mk 1 coach

[geoedlegg]

Hi, what was the brake force in long tons, of a mk 1 coach and or brake coach?

bit of a weird question but I cannot find this information anywhere

 

[class 9]

As a rough calculation, for freight wagons Brake force is half the tare(empty) weight, so for coaches about the same.

 

[100andthirty]

For coaches where the tare to gross weight difference is quite small, the brake force would be something in the range 15% to 20% of the tare mass

 

[hexagon789]

Hi, what was the brake force in long tons, of a mk 1 coach and or brake coach?

bit of a weird question but I cannot find this information anywhere

I had an idea how to figure this out - accident reports.

These usually list the total weight of the train and crucially its brakeforce in tons.

I looked at a few to get an idea but I'll give an example of just one as I think that's sufficient.

The 1969 Morpeth derailment.

In this incident the train was formed of a Deltic and 11 Mk1 coaches, the train weight including loco was 498 tons and its total brakeforce was 376 tons.

While the Mk1s weigh different amounts due to bogie type etc adding up the figures this gives 397 tons of coaches.

A Deltic has a brakeforce of 51 tons, so we are left with 325 tons brakeforce of the 397 tons of carriages.

I get an average weight of about 36 tons for a carriage and an average brakeforce of 29.5 tons or around 82% braked weight.

Hopefully that's of some help

 

[Cheshire Scot]

Back in the days of vacuum braked freight trains, if a passenger coach was included in the freight train formation the brake force was assessed as 50% of it's tare weight - this might perhaps have been a 'safe minimum' assessment to cover for variations in the characteristics of individual vehicle types.

 

[edwin_m]

Does anyone have a definition of brake force? It can't be simply the retarding force applied by a vehicle when the train is braking (opposite of tractive effort), otherwise the Mk1 quoted above would decelerate at 82% of gravity. The nominal figure required by standards for tread braked trains is 7%, which would include the possible lower braking rate of the locomotive.

 

[Dunfanaghy Rd]

Lots of BR loco, carriage and waggon diagrams here:

Barrowmore Model Railway Group (BMRG)

Looking at carriages, Mk i's seem to have a BF of 19 tons on tares of the order of 32 to 35 tons.
Pat

 

[Cheshire Scot]

Lots of BR loco, carriage and waggon diagrams here:

Barrowmore Model Railway Group (BMRG)

Looking at carriages, Mk i's seem to have a BF of 19 tons on tares of the order of 23 to 35 tons.
Pat

Without having checked the linked file I find it hard to believe any Mk1s were as low as 23 tons - BGs and non corridors would surely be the lightest at around 30 tons with sleepers and some catering vehicles up to around 40 to 41 tons (much more than the max. 35 tons quoted). Obviously there would be variances within individual vehicle types according to what bogies were fitted, commonwealth being the heaviest.

Maybe I need to research the file, which does look - at a glance - as if it provides a huge amount of historical interest, so many thanks for the link!

 

[Dunfanaghy Rd]

My bad. I have edited the 23 tons to 32 tons.
Pat

 

[Cheshire Scot]

My bad. I have edited the 23 tons to 32 tons.
Pat

thanks for clarifying, having now delved into the files a little there is a some fascinating detail. Great find.

 

[Inversnecky]

I had an idea how to figure this out - accident reports.

These usually list the total weight of the train and crucially its brakeforce in tons.

I looked at a few to get an idea but I'll give an example of just one as I think that's sufficient.

The 1969 Morpeth derailment.

In this incident the train was formed of a Deltic and 11 Mk1 coaches, the train weight including loco was 498 tons and its total brakeforce was 376 tons.

While the Mk1s weigh different amounts due to bogie type etc adding up the figures this gives 397 tons of coaches.

A Deltic has a brakeforce of 51 tons, so we are left with 325 tons brakeforce of the 397 tons of carriages.

I get an average weight of about 36 tons for a carriage and an average brakeforce of 29.5 tons or around 82% braked weight.

Hopefully that's of some help

Interesting. So measuring brake force in tons is a way to measure it against the weight of the consist.

 

[hexagon789]

Interesting. So measuring brake force in tons is a way to measure it against the weight of the consist.

Seems to be the usual way of doing it rather than as a force in Newtons or kN