37s aren't allowed to run at MU speeds, so it would be the lower speed in that scenario. Most drags have fairly low top speeds anyway
The 57s were designed specifically to be able haul a 9-car Pendolino at 95mph and supply a full ETS load of the same.
Because it is was fully braked while dragged by a 57.
Such a thing does exist IRL, you may know that anyway, so in that case a higher running speed would of course be permissible though whether that is the maximum of the lowest speed vehicle in the formation or a lower figure still I've never seen stated.
the story I'd read was the Paxman Valentas didn't enjoy being at fast tickover all day providing ETH to the MK3s. So the TDM remote control system was tweaked to allow the Paxman to deliver traction power in addition to that of the class 91. This led to some spirited performances....
The story I read was that both were true; 91-hauling the HSTs that were just idling to provide ETH (and zilch to the traction motors) made the Valentas and the traction motors unhappy. As you say, spirited performances.
Is that 45mph a safety factor because the units haven’t been commissioned yet because their maximum speed is 50mph?
Didn’t think of that actually. They’re delivered with Class 7 headcodes on the UK Network, I don’t know if that’s standard for a drag with barrier wagons or if class 5 is the norm for any unit drag.
Class 7 denotes a 45mph limit, presumably identifiying clearly to signallers that it is restricted to a low running speed so as not to unduly hold up other services when regulating.
As I understand it, class numbers can be allocated such that the train can actually travel faster than the speed associated with the initial digit but not slower than. So a Class 7 may actually run at 50mph but would I assume be timed for 45mph. It wouldn't be run at 40mph for example.
It's a class 7 because it's limited to 45mph. If it was 50mph it would be a class 6.
It's the other way around. The speeds are the maximum allowed for that class, but they can be lower (but higher than the maximum speed for the next class down). So a class 7 is more than 35mph, but no higher than 45mph
Thank you, I thought I might have it backwards, but it was a 50/50 choice and of course you always pick the wrong one!
No worries. I'd be very interested to know how often freight trains are timed for speeds lower than the maximum for that headcode - there must be a reason for the rules applying but I'm not aware of any examples myself.Thank you, I thought I might have it backwards, but it was a 50/50 choice and of course you always pick the wrong one!
My ultimate logic was based on thinking you wouldn't want to run slower than the Classification, but of course it's more not wanting to run slower than the schedule timings - the train Class speeds are a different thing to that, I should've thought of that.
Never mind, thank you for clarifying.
Thank-you for the explanation.
Adverse gradients? I imagine up Shap some freights have to be timed considerably slower than their class (or the line speed) would suggest.
