The effect of passenger loadings on train performance

[YorkshireLass]

Hi there,

This is probably a question for the drivers out there: how significant is the number/total weight of passengers on the performance of a train. E.g. can you tell from the cab when you apply power that you’ve got a full and standing train?

Or is the additional weight of passengers compared to the weight of the unit a reasonably small?

Are there any locos/units where high loadings have a particular effect?

I don’t work on railways or have much knowledge at all but it’s something I’ve been wondering.

Many thanks.

 

[hexagon789]

Hi there,

This is probably a question for the drivers out there: how significant is the number/total weight of passengers on the performance of a train. E.g. can you tell from the cab when you apply power that you’ve got a full and standing train?

Or is the additional weight of passengers compared to the weight of the unit a reasonably small?

Are there any locos/units where high loadings have a particular effect?

I don’t work on railways or have much knowledge at all but it’s something I’ve been wondering.

Many thanks.

It can be noticeable on full and standing trains, affecting acceleration. Braking wise it shouldn't really affect modern trains as the braking system has load-sensing equipment to compensate, indeed it can actually make the brakes slightly better on fuller trains.

 

[bastien]

Check my maths here... Wikipedia says a 12 car class 700 weighs 410 tons. It carries 666 seated and 1088 standing.

At 75kg each, that's another 131.55 tonnes. Which seems quite significant!

 

[hexagon789]

Check my maths here... Wikipedia says a 12 car class 700 weighs 410 tons. It carries 666 seated and 1088 standing.

At 75kg each, that's another 131.55 tonnes. Which seems quite significant!

Bit more than I had thought.

 

[bastien]

Bit more than I had thought.

They're a bit of an outlier in weight/capacity terms. The 345s are 1500 people (112.5 tonnes) in a 264 tonne train, though. Crazy.

 

[hexagon789]

They're a bit of an outlier in weight/capacity terms. The 345s are 1500 people (112.5 tonnes) in a 264 tonne train, though. Crazy.

Wow, I still think my +10% estimate is a bit low though for even a long-distance train perhaps.

 

[bastien]

Wow, I still think my +10% estimate is a bit low though for even a long-distance train perhaps.

I'd love to know the *actual* weight of some of the crush loaded 2 car 158s I've been on. Who knew you could fit a dozen people in the cab end vestibule alone?

 

[hexagon789]

I'd love to know the *actual* weight of some of the crush loaded 2 car 158s I've been on. Who knew you could fit a dozen people in the cab end vestibule alone?

I've seen that and worse on 156s running Alloa-Queen Streets, the cycle space becomes a very handy staying area.

 

[jamesbwxm]

I'd love to know the *actual* weight of some of the crush loaded 2 car 158s I've been on. Who knew you could fit a dozen people in the cab end vestibule alone?

Anyone who's been on the train from Wrexham to Chester around 11am on a Raceday I'd imagine. Not an experience I'd like to repeat ever again.

 

[edwin_m]

In principle, acceleration at low speeds won't be affected because it is limited by adhesion. A heavier train is able to exert more tractive effort, but requires more tractive effort to accelerate it, so the weight cancels out.

At higher speeds the acceleration is limited by available power so it will reduce in proportion to the extra weight.

 

[greyman42]

On dmu's, would the amount of fuel in the tanks be significant on a full and standing train?

 

[hexagon789]

On dmu's, would the amount of fuel in the tanks be significant on a full and standing train?

Weight-wise a good bit I would think.