Steam Dreams with 4MT

[SquidvT]

ivor, try daves Dampers fix, it really transforms the engine (for the better now Ive had some time to test it). It still not invulnerable but gives it a bit more poke

[Carinthia]

In my opinion, the power of the 4MT is about right. It will take a bit of a long story and a digression about Black 5s so please excuse the waffle - there is a reason for it.

Not long after the Western lines of Scotland Lines route was released I tried creating a scenario for the midday "Paddy" boat train from Dumfries to Stranraer. This service started at Newcastle on Summer Saturdays in 1962 but was just a connection off a Carlisle service at Dumfries on other days, but still ran class 1 with limited stops. I set this up with a Black 5 and a realistic load of five Mk 1s. It took me some time to make it playable owing to two separate sound issues that were very distracting but when I finally sorted those I was very pleasantly surprised to find that if I adhered to the speed limits, including passing all single-line signal boxes at 15 mph to emulate the exchange of tablets, the Working Timetable schedule fitted perfectly despite, in setting up the scenario, some station to station performance settings had to be raised above 80% whilst others were below the default 75%. With a lot of concentration on the driving up hill and down dale, everything just seemed right - very satisfying.

Today, I had to spend most of the day indoors waiting for a telephone call. I took the opportunity to set up a scenario for the morning Stranraer to Dumfries stopper, again from the 1962 WTT. I even included two extra Fridays only stops which are not timed but "allowed for in the schedule" - skipping those would have been cheating. The load was the typical three coaches plus a vanfit and I put a 4MT on the front, as it often was. Again, the performance setting to achieve booked times varied considerably, ranging between 45% and 85%. And guess what, everything went like clockwork (again, driving needed much concentration) and although a few station arrivals seemed a bit tight I earned a green tick at the end of the 2.5 hr journey!

I know much depends on driving technique so here is what I did, and I made a very interesting discovery. Not being the best of train drivers, I drove in F4 mode with Otto the Fireman and my target was to keep the boiler pressure indicator green (i.e. not losing steam) as much as possible. This wasn't necessarily wise for at times I blew of some decent steam that I could have made good use of. Apart from blowing off and injector activity, I sustained the green except on a few long. steep gradients. With better skill and route knowledge this could have been done more often, especially near station stops where pressure again builds up quite quickly.

In trying to keep it in the green I made a big discovery. There are areas in the cut-off settings which produce good power that I haven't used on any other locomotive. I found at medium speed she was able to accelerate on 8% cut-off, and I even used 5% at times on the level. I recently read that of main line engines, only Royal Scots behaved like that, although others would regularly use 13% which TS engines don't seem to cope with at all. But this one does!

Two examples of settings that kept me in the green:
100% regulator, 13% cut-off, 1 in 77 gradient - I was actually accelerating when around 24 mph
97% regulator, 8% cut-off, 1 in 82 gradient - I was actually accelerating when around 30 mph
If that's not power, what is?

I did find that above around 29 mph, you need to start reducing the regulator to remain in the green and even with it below 50% and the 8% cut off there is acceleration on level and three-digit inclines but speed does tail off above 50 and I didn't ever get near to the permitted 60 mph in places. But I didn't need to to keep time.

So there you are, not a truly scientific test but for my money the power is right on the dot. Just, perhaps, achieved a little differently than we are used to.

John

[SquidvT]

Intresting stuff John. I was inclined to agree with you, but in my own scenario (A 4 coach working from Dumfries to Stranraer) my 4MT Struggled up the longer climbs. I dont think 4 Coaches is excessive, Im sure ive seen photographs of 4mts working the same load on the same route. With Daves damper fix (which I think will be in the official update) things are quite a bit different. Not massively so (for example going up a 1/100 at around 37 mph but still maintaining steam) but it allowed me to make the run in suitible time and without a superhuman effort. Who knows? I guess its down to what we individually feel is right. But as you know for its size the 4MT was considered to be a good steamer and puller.

(PS I dont suppose you have a copy of that WTT do you? Would love to check my guestimate timings against the real thing)

[Carinthia]

Intresting stuff John. I was inclined to agree with you, but in my own scenario (A 4 coach working from Dumfries to Stranraer) my 4MT Struggled up the longer climbs. I dont think 4 Coaches is excessive, Im sure ive seen photographs of 4mts working the same load on the same route. With Daves damper fix (which I think will be in the official update) things are quite a bit different. Not massively so (for example going up a 1/100 at around 37 mph but still maintaining steam) but it allowed me to make the run in suitible time and without a superhuman effort. Who knows? I guess its down to what we individually feel is right. But as you know for its size the 4MT was considered to be a good steamer and puller.

(PS I dont suppose you have a copy of that WTT do you? Would love to check my guestimate timings against the real thing)

Aha, I didn't say it didn't struggle - it certainly did! But the implication is that enough time is allowed for that so we must assume they did struggle. In this fast, high power diesel and electric era it is sometimes easy to forget that many steam services rarely anywhere near official line speed, even on the straight and narrow.

Here's the schedule:


Note that there are no half-minutes in this WTT. I wouldn't be surprised if it was expected that the one-minute stops were achieved in less, so my rigidly-applied sticking to arrival times may have been unnecessary torture.

Good luck. Hope you get the same (or better) results as I did! With that damper fix and manual firing you should do substantially better!

In due course I will be releasing the scenario through my site but there is other traffic (what little there was) and static stock to add yet, plus all the 2.5hr tests I will no doubt need to do, so it will be a little while.

John

[SquidvT]

Excellent, thanks for posting that, ill see how my timings compare and how hard I have to drive/hold back to meet them

[spellow3010]

A good read John - many thanks for taking the time to share those experiences.

I must admit to never having tried driving a steamer on the TS2013 at such low cut-off levels. Will have a dabble and see if it improves my performance and that of my trusty 4MT. I'm normally up around 40 down to 25% cut off at medium and higher speeds.

Cheers