Any MidEast Experts.

Lad491 · Post by **Lad491** » Mon Feb 23, 2004 10:45 am

Hi Guys. Ive just started writing an activity for the mideast and ive encountered something strange at St. Neots.

I have deliberately engineered some delays to services at St.Neots that results in trains "stacking up" behind each other. The player service (HST) is following closely behind another AI HST on the down fast. There are 3 down slow services arriving outside St Neots at the same time. A 47 + coaches, following the 47 is a 2 car DMU and following that is a coal train.
All 3 trains are scheduled to cross onto the down fast to run into the station and then back onto the down slow.

As the AI HST clears St Neots onto the down fast, the 47 is cleared into the station just as you arrive at the outer home so you get checked at a red as per the plan. However, once the 47 clears the station, the DMU which has now arrived on the down slow outer home is given priority over the down fast HST player service. This has resulted in the player service HST receiving a 10 minutes signal check instead of the planned 2 minutes or so.

Ive tried tweaking times of the DMU but it seems that passenger services on the down slow always get priority over down fast services. Making the DMU arrive later just adds to the time the HST is delayed.

Anyone else come across this? I expected MSTS to give priority to the player service as soon as the road became clear but this doesnt seem to be so in this case.

Any thoughts would be appreciated.

Laurie

Fodda · Post by **Fodda** » Mon Feb 23, 2004 12:14 pm

A pure guess, but when your player train is stopped, might it be dragging back on the brakes slightly and showing the reverse track monitor? If this is so, then you will lose the road ahead as the sim thinks you're moving backwards...

Lad491 · Post by **Lad491** » Mon Feb 23, 2004 1:54 pm

Hi Fodda.

Nope - thats not the reason. Track monitor still showing forward.
Ive spent the morning adjusting the times of the 47 and dmu so the 47 gets there slightly earlier and the dmu slightly later but the result is always the same. I sit at the red for 10 minutes happily watching trains pass me on the down slow.

Its puzzling me

All i can think of is to switch the player train onto the down slow ahead of the dmu so as to get right of way.

Strange thing is that in the activity editor everything works fine with the player service getting a green light as soon as the 47 leaves st neots, leaving the dmu sitting outside on the down slow waiting for the road. But we all know that the activity editor doesn't run trains like it does when you actually run the activity for real.

Fodda · Post by **Fodda** » Mon Feb 23, 2004 2:05 pm

LOL... The "video player" in the AE has a mind of its own that's for sure.

Oh well, as I said only a guess.

Perhaps you could route the player service through the down slow, in which case you could put some sort of possesion on the down fast line to make it believable. Maybe a track-laying train and team... Or perhaps a waiting steam day out on the fast that has to wait for you to pull through... Or even a derailment. Put a train in there with a train and crane consist in front of it, or better, have the train and crane pass the player either before or after the 'derailment'.

ianm42 · Post by **ianm42** » Mon Feb 23, 2004 2:34 pm

Did I read somewhere that the priority is to do with the starting times of the services? Try making the DMU service start early/later from further/closer to St Neots and see if that has the required effect.

simont · Post by **simont** » Mon Feb 23, 2004 6:04 pm

Also, a red signal seems to send you down the priority ladder. You may be able to use the old double reverse point to keep the DMU behind you. That bottleneck at St. Neots is a pain in the arse though- whenever I create Mideast activities I tend to cheat, and send local services down to Eaton Socon and up from Houghton.

Geoffwright · Post by **Geoffwright** » Mon Feb 23, 2004 6:59 pm

You can also try adding three one second waiting points in the DMU path at or just before St. Neots. This will stop it grabbing the path. However, be very careful, waiting points are strange & once you have included them in a path you can NEVER subsequently edit the path without generating broken points. You then have to recreate the path from scratch.
The waiting point technique obviates the need for awkward reversing points with the need to carefully adjust the spacing to match the consist length, but has the above severe disadvantage. For a player service, multiple waiting points produces a visually better output, but for an AI service you're probably better off using the twin reversing point technique to stop that train grabbing the path too early.

Lad491 · Post by **Lad491** » Mon Feb 23, 2004 7:36 pm

Thank you all for your suggestions. The main problem with double reverse points and waiting points is that it will affect all trains on that line, but i dont want to hold up the 47 which gets the all clear just as i approach the down fast red where i expect to get stopped. Ive tried tweaking departure times of the dmu but i have a very small window of just a couple of minutes without impacting on subsequent services.

Im going to play with it some more later in the week. One other solution i had was to delay the player service departure by 5 minutes. The 47 has gone by the time you reach st neots which is a pity as its quite cool to draw up alongside it at the signal and then see it pull away, but by doing that the dmu is waiting and gets the road as you arrive and the player service only has a 4 minute wait rather than 10 minutes.

I think thats going to be the way out of the problem but i'll tinker some more. Thanks for your suggestions.

Laurie

MartinH · Post by **MartinH** » Mon Feb 23, 2004 9:21 pm

Double reverse points and waiting points will only affect the services that use that particular path, so if you only want to affect one service, only use the path for that service.

I wrote most of the original Mideast UK activities along with Alan Salmon and the bottleneck at St Neots is very difficult to deal with. I tried to be clever on a number of occasions and found myself giving up in disgust. The key to AI traffic, especially in jams like this, is not to start everything off too close together. Don't force a traffic jam, but encourage one to build up naturally by running slow trains in front of fast ones. Whatever you do, don't start off trains within 3 (or is it 4 on this line) signals of each other or you will get chaos. I seem to recall that on my activities all of the southbound expresses started at Retford and the locals from Peterborough, so many had been running for an hour or more before you actually passed them.

Martin

suffolk · Post by **suffolk** » Mon Feb 23, 2004 9:33 pm

Lad491,

Not trying to preach to the converted but remember when you write and plan an activity especially one with a complicated event like you're planning, you test and test it time and time again until you get it just right but driving the way you drive, then someone downloads it and drives either faster or slower and the whole plan goes out the window and ends up with a stalemate between the traffic.

mazda · Post by **mazda** » Mon Feb 23, 2004 10:58 pm

Not sure that I've got the picture completely right, but slow trains will in effect get priority wherever slow and fast trains converge. This is the inevitable outcome of MSTS's first come, first served AI contoller.

If your slow line traffic is running at 60MPH and your fast line at 120MPH and the two are due at the convergence of the slow and fast lines at St Neots at the same time, then your slow traffic might tie up the junction for, say, 3 minutes before it gets there while your fast path only reaches the interlocking 1.5 minutes before it arrives (assuming 3 signals a mile apart). Net effect - 3 minutes before reaching the spot your slow traffic is 3 miles out and has already got the 'road' - your fast train is still 6 miles out and is going to be forced to give way to the slow.

Not sure I got the picture in my head but if this is the problem this is where you can use double reverse points on low line paths to set priorities through the junction.

I've been working on a massive 'master traffic file' (150+ services so far) for the Mideast and use double reverses extensively to set priorities through interlockings. Without them the fast trains get held up all over the place.

Hope the above helps in soem way

Cheers

Greg

MartinH · Post by **MartinH** » Mon Feb 23, 2004 11:31 pm

I recall using double reverse points in the "overtaking sidings" on the double track sections so that the coal trains wouldn't get in the way of the expresses. The player hardly ever saw this happening, but if you didn't do this, you got a coal train with several expresses all stuck behind it. I'm afraid I can't remember much more than that - it's 18 months since I last wrote activities for this route. Where's the time gone?

Martin

saddletank · Post by **saddletank** » Tue Feb 24, 2004 12:44 am

mazda wrote:I've been working on a massive 'master traffic file' (150+ services so far) for the Mideast and use double reverses extensively to set priorities through interlockings. Without them the fast trains get held up all over the place.

The problem with this is that MSTS has to cruch all that AI traffic data in the activity and this can cause MSTS to crash. I know Pat Dalton had this problem on Skipton, and I fear it is affecting one or two activities on Highworth.

Although it is a lot more work, it is more computer efficient to have AI paths that are short in time and distance but place them skilfully so the player who is keeping to his timetable gets to see them. If they vanish 400yds behind him he is none the wiser and MSTS has a lot fewer numbers to handle.

mazda · Post by **mazda** » Tue Feb 24, 2004 3:07 am

Martin

Apart from the Activity Editor taking a while to fire up I haven't had any problems with the amount of data crashing the simulator.

Everyone has their own preferences so I'm not criticizing the AI traffic materialising and dematerialising way of doing things. I guess I don't find it particularly interesting because it simply uses the AI traffic as a form of theatre.

What I enjoy is creating a 'timetable' of services where each service either commences in a siding or terminal platform and runs to a siding or terminal platform and where the paths' priority is set using double reverse points as they flow onto or off running lines, faster lines and so on. While developing all this my 'player service' is simply an engine in the most isolated siding I can find, so as not to interfere with anything! The real test is if you can jumble the starting times of all your services and have everything resolve itself so all the trains eventually reach their destinations without undue delay. Good fun to watch in the Activity Editor!

Finally, having simulated the railway's operations, you can go back and use any of the timetabled services to create a player service - just use that service to replace your engine in the siding, save the master traffic file under a new name (with what is now your player train deleted) and you have an instant activity. Each activity based on the Master Activity takes about two minutes to create. This means that in 10 minutes you can create 5 activities - all of which are complete with lots of AI traffic! The really fun bit then starts as you watch how your train interacts wth the AI traffic.

With the Mideast, I've tried to simulate operation (loosely based on the services listed in the May 1979 Thomas Cook International Timetable) for a period from 4am-12noon. I've finished all the passenger services and am just finishing off the freight. I've used Mideast 1.3 CD default stock (apart from a couple of freight wagons) so that if I ever finish the thing all I have to is upload the Master Activity and others can then use the Master Traffic file to create endless activities. By the time it is finished there should be a couple of hundred possible activites embedded in that one traffic file.

So far it works pretty well - 90% of the activities created this way come to a happy ending. And by the way, long paths do not mean bad frame rates. As I've progressively added services there has been NO perceptible drop in frame rates. Only the trains that are visible effect frame rates.

Anyway, this business of activity creating is endlessly fascinating. If you make the paths varied enough you will, without even trying, end up with lots interesting situations such as that which Laurie (remember Laurie - this was his post!) is trying to orchestrate.

Cheers

Greg

Lad491 · Post by **Lad491** » Tue Feb 24, 2004 7:25 am

Interesting replies - thank you everyone. Mazda your Master Activity file sounds great for people who just need to churn out activities to order, but i find half the fun in activity writing is to solve the sorts of issues I have and I think I would soon get very bored with it.

The jam at St Neots has been deliberately engineered by me, I want a holdup there and want the player service to get a red signal. The problem is i expected the player service to take its turn so that as I arrive the 47 on the slow is given right of way, then the dmu arrives on the slow and gets held and then i get right of way. This is what isn't happening.

Suffolk I take your point entirely, in fact its something I have spent hours practising on my L2B activities. Once I have the activity written and working I then usually try to vary my driving style by driving slower to see the effect it has.

BTW - I have created completely new paths for all of my services all starting at Welwyn or Retford and finishing in the same place but i take Martins point ( and i have used his technique before as well ), because the performance of AI trains is variable I sometimes use shorter paths to make the train "appear" at the desired location at the right time.

Thanks again for your comments guys - I'll do a bit more work on this at the weekend and let you know how it comes out.