Vacuum Brakes

[slipperman12]

Hi All,
Last week, I ran Eric's Pines Express activity on my favourite route, the Somerset & Dorset, using MSTS. I needed three attempts to get to Bath from Evercreech Jcn, due to the loco running out of steam. Even then, I was still late arriving at Bath! This got me thinking about Open Rails, particularly now, as there seem to have been some improvements for dealing with vacuum brakes.

The Player loco is 92220 Evening Star, fitted with a headboard (using an invisiwag).

My first run was using OR version X3996. The loco wouldn't move until the regulator was at 83%, with copious amounts of smoke. The invisiwag was "Vacuum-Piped" and I know there had been problems with that configuration, so I removed all references to vacuum brakes from it. The loco now started reasonably well with the regulator at 21%, but I didn't continue with the run.

My second run was using X4003, with the invisiwag restored to its original state. BOY!! was there a difference?! The loco started moving at 5% regulator, so I continued with the run. The first stage of the activity is to reverse the loco on to its carriages at the platform. This is where there's a problem - the time taken for the brakes to apply and to release appear to be very long (comparatively, with MSTS), even for a light engine and tender. This would seem to make any activity which involves shunting impracticable. In this activity, I either stopped before reaching the carriages, or hit them rather smartly!

Driving the steam loco itself was better than MSTS (although I'd like the steam generation rate to be included in the F5 display, along with the steam usage rate). Unlike with MSTS, I didn't run out of steam anywhere in the whole activity. The main problem was braking for the various speed restrictions and, of course, station stops. As it was, I was 15 minutes late at Evercreech Jcn and about 30 minutes late at Bath. One element I do like is the indication of the gradient on both the F4 & F5 displays; it's very useful.

I appreciate that it may just be a case of me getting used to the braking characteristics, but I still feel that any shunting activities would be a definite no-no! In the (hopefully) short term, is there a setting in the .eng file which may be adjusted to speed up the brake application/release rate?

May I take this opportunity to wish the Open Rails team all the best for Christmas and the New Year and to thank them for the great enhancements they have made over MSTS, like operating turntables, timetables, the ability to switch to any other driveable consist.... It's a long list!

Cheers,
Ged

[DarwinS]

Hi,
The OR team have recently started work on vacuum brakes.

So far this has reached the point of having realistic application times and release times for a medium length passenger train.
[That is about 30 seconds to release from 0 in Hg to 21 in Hg and about 12 seconds for the last coach to reach 0 in Hg in an emergency application.
The application time is less if the train has direct action valves and it is now possible to write those into OR wag files.]
Release times for vacuum brakes are relatively slow, so if you are working a stopping passenger train try to have 14 to 16 in of vacuum when you pull up, or at least before you are ready to leave again.

Due to differences between air brakes and vacuum brakes the times do not yet adjust as they should for different train lengths.
Hopefully this can be remedied soon.

You may find when using MSTS files in OR the brakes are further slowed down because of the way that .wag files were written in MSTS.
Many people including myself wrote the MSTS files in such a way as to try to slow down the brake application and release in MSTS because it was far too fast.
Hopefully when work is complete replacement Open Rails files will become available for most MSTS stock so that you will get realistic performance in OR.

Still to do is work on train length, GWR vacuum brakes and diesel and electric loco vacuum brakes.

92220 was fitted with steam brakes for the loco and these would have had almost instant application and release when running light engine. I can not yet say if it will be possible to add steam brakes to OR, but I would certainly like to see them.

[DarwinS]

I am trying to compile some information about vacuum brakes to help OR users to write realistic eng and wag files in the future.

For more information see:

http://forums.uktrainsim.com/viewtopic. ... 3&t=148867