Topic: Tram running costs

[Vladki]

I notice that modern trams are quite expensive to run in comparison with blackpool trams. I don't know if any balancing or real world values were used, but this is my observation:

Most of the single car trams (both single and double deck), are priced at 0.20 - 0.40 c/km, and about 16 c/month.
Notable exceptions are:
Blackpool coronation (1953): 0.10 c/km
Blackpool twin (1958): 0.10 c/km
Balckpool jubilee (1979): 0.08 c/km
Blackpool centenary (1984): 0.05 c/km
Blackpool millennium (1998) 0.06 c/km
Was there such significant increase in power efficiency, or reduction in electricity costs in 1950's and 1980's ?
I could expect a reduction in monthly costs in 1970-80's due to one-man operation (no conductor on board). But the monthly costs are roughly the same.

And then come the modern beasts (2-part)
bombadier flexity swift: 0.48 c/km, 31.22 c/month, 480 kW
Metrolink T68: 0.42 c/km, 31.66 c/month, 420 kW
midland metro T69: 0,96 c/km, 31.22 c/month, 960 kW --- WTF? twice as much power and running cost as T68?
According to https://en.wikipedia.org/wiki/West_Midlands_Metro_rolling_stock#T-69  it has 4x105 kW - so should have same power and similar costs as T68

3-part trams:
siemens-duewag 1.10/km 31.20/month, 1.1 MW, 80 km/h
sheffield cossloh 2.22/km 31.20/month, 1.1 MW, 110 km/h -- why is it 2x more expensive to run. Just because it can go faster?

5 and more part-trams:
CAF Urbos3 (midland) has similar costs as stadler and flexity 2, but caf edinburgh (built as 5-pieces) is 2x more expensive and also 2x more powerful.
Wikipedia says about
CAF edinburgh: 7 parts (8-axles), 12 x 80 kW.  I wonder how they are spread over the 8 axles?, maybe 2-0-4-0-4-0-2 ? Total 960. But we have 4x80 kW in each powered part. So that is clearly too much, and running costs should be adjusted accordingly.
CAF midlands: 5 parts (6-axles), also 12 x 80 kW. So which one is true? But we have it at half power.... But at least it sort of matches the other 5-part trams...

[DrSuperGood]

The costs were roughly calculated based on the vehicle power with a lot of guess work.

[Freahk]

Also see This Thread for a quite detailled explaination how the balancing currently works.

In general it's roughly the more power, the more expensive with a little guessed input power per output power factor.

CAF edinburgh: 7 parts (8-axles), 12 x 80 kW.  I wonder how they are spread over the 8 axles?, maybe 2-0-4-0-4-0-2 ? Total 960. But we have 4x80 kW in each powered part. So that is clearly too much, and running costs should be adjusted accordingly.
CAF midlands: 5 parts (6-axles), also 12 x 80 kW. So which one is true? But we have it at half power.... But at least it sort of matches the other 5-part trams...

CAF states a Composition of Mc-S-T-S-M-S-Mc for the Edingnburgh and Mc-S-T-S-Mc for the Birmingham trams but I couldn't find out what these actually mean.
S cars actually don't have any axles.
I guess Mc is Motor cab and M is motor.
That assumed, Edingnburgh tram should indeed have 12x 80kW, whereas CAF Birmingham should have 8x80kW

[Vladki]

S cars actually don't have any axles.
I guess Mc is Motor cab and M is motor.

And T is trailer (2 axles but no motor) ?

[Freahk]

And T is trailer (2 axles but no motor) ?

I'd at least expect that but cannot say this for sure without an UIC wheel arrangement or something simmilary detailled.
That Mc-S-T-S-M-S-Mc doesn't follow any norm or at least I didn't find this norm defined anywhere and the meaning of it is not defined on the CAF page, so I can only place guesses.

Edit:
According to this page,
CAF Urbos3 in Edinburgh have a Bo+Bo+2+Bo wheel arrangement.
Bo means two individually accelerated axles (i.e. the axle does not share it's engines with other axles)
2 simply means two trailing axles.
"floating" cars are ignored in UIC, as it's all about axles, not about cars.

Birmingham is Bo+2+Bo

So my guess seems to be correct.

[Vladki]

I have put the parameters into spreadsheet, and checked the runningcost/power ratio:
From 1880-1920 it is about 0.6
From 1920-1960 it is about 0.4 with the exception of blackpool-ee-railcoach (0.26), and blackppoool twin (0.12)
Around 1980 it is 0.15 and gets lower to 0.10 in 1990. Except for blackpool-centenary (0.06)

I think their power was recently adjusted but the costs were not:
https://forum.simutrans.com/index.php/topic,19622.msg185039.html#msg185039
And ideed, blackpool-centenary with the old power figure has cost/power ratio 0.10 and blackpool-ee (0.41), blackpool-twin (0.2)

So here are the fixed runningcost figures for running costs:
blackpool-ee = 34 (same as blackpool-balloon)
blackpool twin = 17
blackpool centenary = 8.5 or 9 if whole numbers are needed

Code: [Select]

diff --git a/trams/blackpool-centenary.dat b/trams/blackpool-centenary.dat
index d6ac6608f..37dcd634d 100644
--- a/trams/blackpool-centenary.dat
+++ b/trams/blackpool-centenary.dat
@@ -21,7 +21,7 @@ overcrowded_capacity=16
 weight=17.5
 axles=4
 cost=434000
-runningcost=5
+runningcost=9
 fixed_cost=6362
 sound=tom-tait-tram.wav
 
diff --git a/trams/blackpool-ee-railcoach.dat b/trams/blackpool-ee-railcoach.dat
index dfabe9d3e..759886b95 100644
--- a/trams/blackpool-ee-railcoach.dat
+++ b/trams/blackpool-ee-railcoach.dat
@@ -22,7 +22,7 @@ overcrowded_capacity=6
 weight=11.4
 axles=4
 cost=410000
-runningcost=22
+runningcost=34
 fixed_cost=6342
 sound=tom-tait-tram.wav
 
diff --git a/trams/blackpool-progress-twin-power.dat b/trams/blackpool-progress-twin-power.dat
index 21597a266..135955a8d 100644
--- a/trams/blackpool-progress-twin-power.dat
+++ b/trams/blackpool-progress-twin-power.dat
@@ -24,7 +24,7 @@ weight=13
 axles=4
 cost=352000
 upgrade_price=12500
-runningcost=10
+runningcost=17
 fixed_cost=6293
 sound=tom-tait-tram.wav


[Vladki]

Further fixes for T-68 and T-69, which according to wikipedia should have the same power.

Code: [Select]

diff --git a/trams/metrolink-t86-back.dat b/trams/metrolink-t86-back.dat
index ae92a8079..3a597e2c7 100644
--- a/trams/metrolink-t86-back.dat
+++ b/trams/metrolink-t86-back.dat
@@ -21,7 +21,7 @@ payload=41
 overcrowded_capacity=58
 weight=22.5
 brake_force=29
-axles=4
+axles=3
 cost=0
 runningcost=21
 fixed_cost=6000
diff --git a/trams/metrolink-t86-front.dat b/trams/metrolink-t86-front.dat
index 15936c2ac..cd19cfc82 100644
--- a/trams/metrolink-t86-front.dat
+++ b/trams/metrolink-t86-front.dat
@@ -21,7 +21,7 @@ payload=41
 overcrowded_capacity=58
 weight=22.5
 brake_force=29
-axles=4
+axles=3
 cost=800000
 runningcost=21
 fixed_cost=6667
diff --git a/trams/midland-metro-t69.dat b/trams/midland-metro-t69.dat
index f02f27cfb..6e7267b29 100644
--- a/trams/midland-metro-t69.dat
+++ b/trams/midland-metro-t69.dat
@@ -4,9 +4,9 @@ obj=vehicle
 name=MidlandMetroT69Front
 engine_type=electric
 speed=70
-power=480
+power=210
 gear=80
-tractive_effort=52
+tractive_effort=40
 copyright=James
 intro_year=1996
 intro_month=4
@@ -21,7 +21,7 @@ weight=18.2
 brake_force=23
 axles=3
 cost=587500
-runningcost=48
+runningcost=21
 fixed_cost=6490
 sound=zabuhailo-modern-tram.wav
 
@@ -64,9 +64,9 @@ obj=vehicle
 name=MidlandMetroT69Rear
 engine_type=electric
 speed=70
-power=480
+power=210
 gear=80
-tractive_effort=52
+tractive_effort=40
 copyright=James
 intro_year=1996
 intro_month=4
@@ -81,7 +81,7 @@ weight=18.2
 brake_force=23
 axles=3
 cost=0
-runningcost=48
+runningcost=21
 fixed_cost=6000

EDIT:
I'm working further on the 3-part trams - sheffield supertram and sheffield tramtrain.
The have wheel arrangement B / B-B / B   or Bo / Bo-2 / Bo
What I have a problem is how the weight is balanced to get approximately  right axle_load?
Or is it so low anyway that it does not matter?  tramtrain ha 88 t so it makes 11 t/axle on average.
Should I just make the middle (with 2 bogies) have approximately half of the total weight?

[Freahk]

I also did some researching, so we can (hopefully) finally get the specs right.
It's quite hard to find technical data about them these days as most articles (e.g. sources linked in wiki) seem to have disappeared in the meantime. Fortunately, there is webarchives.org.

T68 should be (according to this sheeet)
seats: 86 + 122 standing capacity
empty weight: 49t
acceleration: 1.3 m/s² acceleration -> 64 kN (asumed acceleration is given for empty weight)
braking: 1.3 m/s² -> 64 kN, emergency braking up to 2.6 m/s² ->127 kN using mechanical brakes in addition
power:420 kW
monthly costs: 31.66

It would be nice to have a T68A available from 1999
power: 480 kW
The follwing are guesses from "The three–phase ac motors were lighter, more reliable, require less maintenance and were more cost effective."
empty weight: 48t
kilometer cost: 0.46 = 0.95*0.1*480
monthly costs: 30 = 0.95*31.66

Btw. I gues this thread rather belongs to Pak128.Britain-ex subforums

Oh well, didn't read your above edit yet:

What I have a problem is how the weight is balanced to get approximately  right axle_load?

There is no easy way to calculate this. It greatly depends on the exact position of wheels and exact per-car weight and even if we knew that, we had to place further guesses like weight being evenly distributed over a car, which is often not true.

In fact, train manufacturers may aim at getting as much weight as possible on accelerated axles, as that will help to get more force on rails without slipping.

I'd like to quote the mentioned T68 paper for this: "Under full–load conditions almost 70% of the weight was on the powered bogies, which assisted the hill–climbing ability of the trams."
For T68, that means an axle load of 63.56t*0,7/4=11t (assumed 49t + 208*70kg=63.56t loaded weight)
Which makes me wonder how the current 5t were calculated or assumed?
Even asuming currently used unloaded weight of 45t and assuming the weight was evenly distributed results in 45t/6=7,5t

However, I guess for simutrans purposes it should be fine to assume an even distribution of weight over the train.

In reality, tracks maximum axle load of 17t does not mean none of the axles of the train is ever allowed to exceed 17t. In fact, there may even be exceptions to the "maximum" axle load that do not imply any reduction in speed.
E.g. SNCF, the national railway company of france restriced their high-speed tracks to a maximum axle load of 17t but allows power heads to exceed that maximum by up to 2t
It is assumed that this value was intentionally chosen to allow TGV trains, whose power heads have an axle load of 18t but not allow ICE 1 and ICE 2 trains whose power heads have an axle load of 20t (ICE1) or 19.5t (ICE2)

[Vladki]

Yeah I was looking at T68A too. Also any information about tractive and braking force is mostly guesswork based on values from other trams. So thanks for that information, it could be used to extrapolate others.

About running costs. For some reason the cost/power ratio for trams after 2000 increases again to 0,15 and 0,20 in 2010... Although I would expect further decrease thanks to asynchronous motors.

About monthly costs. Almost all single car electric trams and their trailers have 60-65 c/month. 2- and 3- part trams have 2x60. I would expect that most of the monthly price is the drivers wages, so I would expect that articulated trams do not cost significantly more than single tram. Although there should be a significant decrease in monthly costs in 1970's when one-man-operater trams were introduced in Blackpool. So previously there was a conductor, probably with lower wages than the driver? Old trailers should include only the wages of conductor.

multi-part trams seem also overpriced - 2x60 for front and rear; 12 for middle and 5 for panto sections... Why is the rear section so expensive?

[Vladki]

Which makes me wonder how the current 5t were calculated or assumed?

bug in dat file - t68 has 6 axles (Bo-2-Bo), but the dat had 8 axles. I have huge patch in preparation.

James - important question - is the tractive_effort multipleid by gear or not? If I calculate it from acceleration, should I divide by gear it to account for it?
Looking at in-game info it seems that it is scaled... hmmm more work...

[Freahk]

Are you sure it's not Bo'2Bo' ?
Anyways, I guess I know what you meant.

I guess I'll have to replace many trams soon. To be exact up to 89 T68

James - important question - is the tractive_effort multipleid by gear or not? If I calculate it from acceleration, should I divide by gear it to account for it?

I'm not James, but code said gear IS applied to force, so you will have to divide by gear.

[Vladki]

Are you sure it's not Bo'2Bo' ?
Anyways, I guess I know what you meant.

Whatever. I know how to write steam engine arrangements, but I have no idea about articulated trams (that even have parts with no wheels at all.
Also how do you write jacobs bogies?

I'm not James, but code said gear IS applied to force, so you will have to divide by gear.

:-(

[Freahk]

but I have no idea about articulated trams (that even have parts with no wheels at all.

These cars simply don't appear in UIC wheel arrangements as it's all about axles.

Also how do you write jacobs bogies?

Just like any other bogie. E.g. Bo', whereas Bo without the apostrophe would be two axles that are fixed to the car body.
If you want to clearly point out a jakobs bogie, you can put a dash bove it. That's specified in UIC but practically not used because nobody can type such characters.

[Vladki]

OK, so I have checked the rules to write the wheel arrangement:

Traditional blackpool trams: 2x 40 HP or 2x 57 HP, 2 bogies. I could not find if both axles in a bogie are powered: B'B' or only one axle powered: (1A)'(A1)'. That would make a difference in available tractive_effort.
T-68, T-68A, T-69, Bombardier CR4000 flexity swift: 4x105 kW or 4x150 kW, 3 bogies: Bo'2'Bo'  (middle is unpowered jacobs bogie)
Sheffield supertram:    4x 277 kW, 4 bogies: Bo'+Bo'Bo'+Bo'   (+ is the articulation joint)
Sheffield tramtrain:    6x 145 kW,  three motorised bogies and one unpowered trailer bogie: Bo'+Bo'2'+Bo'

For the long ones I'll add +0+ for parts without wheels
Blackpool flexity: 4x 120 kW: Bo+0+2+0+Bo

These have 2 engines per axle = maybe they have half-axles to achieve 100% low-floor
Croydon variobahn: 8x 45 kW (each wheel has its own engine): Bo+0+2+0+Bo
Bombardier Incentro nottingham: 8x 45 kW: Bo+0+2+0+Bo
CAF midlands: 12x (or 8x) 80 kW: Bo+0+Bo+0+Bo, or Bo+0+2+0+Bo ?
CAF edinburgh: 12x 80 kW: Bo+0+Bo+0+2+0+Bo

Good news is that I found acceleration info for mosto of them.
Bad news is more work on getting them right...

EDIT: about CAF urbos3 - They can be 3,5,7 or 9 parts long. I think it should be represented as only one model in simutrans, allowing thes combinations (according to http://www.strassenbahn-online.de/Betriebshof/LF100/index.html):
Bo+Bo
Bo+2+Bo
Bo+2+Bo+Bo
Bo+2+Bo+2+Bo

I did not find any Bo+Bo+Bo combination (of CAF trams, so the midlands are most probably Bo+2+Bo)
The question is if we want to make complex constraints and force only the above combinations, or allow any variation and length?

[Freahk]

T-68, T-68A, T-69, Bombardier CR4000 flexity swift: 4x105 kW or 4x150 kW,

Is it a typo? Should indeed be 4x105 kW for T-68 and T69 but 4x120 kW for T-68A and CR4000.

CAF midlands: 12x 80 kW: Bo+0+Bo+0+Bo

From my sources it should be B+0+2+0+B in your notation (preciesely, the + is wrong here, better use spaces if you want to point out the end of a car as + has a different meaning). Do you have any source that states it has 12 engines?

Further, I am not quite sure about the current speed limit of the Vossloh/Stadler Citylink "Sheffield tramtrain".
I am quite sure I had seen that 110 km/h stated somewhere but all sourced I have found recently state a maximum speed of 100 km/h.

[Vladki]

Is it a typo? Should indeed be 4x105 kW for T-68 and T69 but 4x120 kW for T-68A and CR4000.

Yes just as you write. I just put them together, as apart from the engine they have similar contruction

From my sources it should be B+0+2+0+B in your notation (preciesely, the + is wrong here, better use spaces if you want to point out the end of a car as + has a different meaning). Do you have any source that states it has 12 engines?

https://en.wikipedia.org/wiki/West_Midlands_Metro_rolling_stock

Further, I am not quite sure about the current speed limit of the Vossloh/Stadler Citylink "Sheffield tramtrain".
I am quite sure I had seen that 110 km/h stated somewhere but all sourced I have found recently state a maximum speed of 100 km/h.

Maybe it is capable of 110 but certified only to 100 ?

[Freahk]

https://en.wikipedia.org/wiki/West_Midlands_Metro_rolling_stock

Well, the arcticle does not cite a source for that.

According to http://www.strassenbahn-online.de/Betriebshof/LF100/index.html it is Bo+2+Bo
According to https://www.caf.net/en/productos-servicios/proyectos/proyecto-detalle.php?p=41 it is Mc-S-T-S-Mc
And finally, according to https://web.archive.org/web/20131203030158/http://www.therailengineer.com/2013/05/03/caf-trams-for-midland-metro-expansion-project/

Three of the modules (C1, R and C2) are mounted on bogies and the other two modules (S1 and S2) are suspended. ... The bogies under C1 and C2 modules are powered with one traction motor per wheel, whilst the intermediate bogie under module R is a trailer.

So it is quite likely that the wikipedia page is simply wrong.

Btw. according to https://www.railwaygazette.com/nc/news/single-view/view/caf-named-preferred-bidder-to-supply-new-midland-metro-trams.html "The contract for 19 five-section Urbos 3 trams with options for up to six more is expected to be signed within six weeks, and will be worth 'in the region of £40m'.", thus roughly £2.1m per tram. I have no idea how real-world purchase costs relate to ingame purchase costs, however.

Sidenote: We really need a more detailled engine/electrification model on the long feature list to properly support all these new hybrid types of vehicles. It seems that concept became quite famous in the last decade.

Maybe it is capable of 110 but certified only to 100 ?

I have no idea. Although the 110 km/h would be quite useful to my regional trams, I am moreover interessted in correct data.
I'll investigate that. Usually, Stadler it quite transparent in vehicle specs.

Edit: 100 km/h is correct, I have no idea where the 110 km/h came from.
https://www.stadlerrail.com/media/pdf/ttsypte0616e.pdf

Yet another edit:
Didn't read your edit before:

I did not find any Bo+Bo+Bo combination (of CAF trams, so the midlands are most probably Bo+2+Bo)
The question is if we want to make complex constraints and force only the above combinations, or allow any variation and length?

Imho, either allow Cab+Intermediate+(Trailer+Intermediate | Powered+Intermediate)+Cab
or enforce Trailer+Intermediate and Powered+Intermediate to be alternating. I don't think we should restrict it to 3, 5, 7 or 9 cars.
Longer trams are simply not needed in the real-world, that's why CAF doesn't officialy offer these. I don't think they would not be able to develope such if there was such a request.

[Vladki]

Discussion about adding T68A (more power, more efficient and reliable motor). But in general T68/T68A were much less reliable than flexity switft that replaced them quickly since 2009. But Flexity swift is available on Croydon Tramlink since the same time as t68A (1998-2000). The Croydon and Manchester Flexity differ only slightly (Manchester is 2 m shorter, 3.5 tons heavier, less seats but more standing space, total capacity is almost same, Manchester high floor, Croydon low floor). Flexity is clearly superior to T68, so why did Manchester buy T68A ? Maybe compatibility of spare parts, crew training, track compatibility? All that is not simulated. So the question is how to balance T68A to be an interesting yet realistic option.

Almost all trams of the same era have constant ratio of runningcost/power = 0,10. So T68A should have higher runningcost to compensate higher power. Thus it would have same runningcost as Flexity, only slightly higher monthly cost, and quite higher purchase cost. We should somehow show that T68A was more reliable and cost efficient than T68, but still worse and more expensive than Flexity. The only option I see is raising the monthly costs for T68, and letting T68A be slightly cheaper but still more expensive than Flexity.

And to make it a considerable option for players, allow upgrades from T68 to T68A, although they never happened.

Hmm, maybe purchase costs were different ? If T68A would be cheaper to buy it would be a viable option - choose either cheaper tram with higher maintenance, or more expensive with lower maintenance...
Flexity for metrolink was £2m a piece: https://www.railway-technology.com/uncategorised/newsmanchester-metrolink-order-20-new-trams/
But I did not find how much was the T68/A


Edit: t68 and t68a should be able to couple to each other. That would be a good equivalent of its real world advantage for Manchester.

[Freahk]

I would be quite surprised if M5000 or CR4000 cannot be coupled to themselves.
Their Cologne equivalent on which they are based definitely can be coupled.
I could not find any images of two coupled CR4000, however, at least an image showing two coupled M5000

M5000

[Vladki]

What I had in mind is that t68a can be used to make pairs with older t68. But you cannot pair t68 with m5000.

So in game decisions would be similar to real world:
- we have some t68 and need to expand: buy compatible t68a
- we are building new network: buy flexity, (cheaper to run)

[Freahk]

- we have some t68 and need to expand

We couple the existing T68 and fill up with new Flexity.

In the real-world the reason to order new T68A is out of scope from simutrans. I's likely they were ordered because they were immediately available, no need to develop a new tram that meets the cosntraints of the network. Even deriving a new one from a platform involves an expensive planning phase, often the production of a prototype, expensive test running.
The whole process would be quite expensive for an order of only 6 trams.
Further, different vehicles require different parts to maintain, which quite disadvantageous given the small number of vehicles.

Another reason might be an existing contract with Ansolda Breda that allowed them to order new trams the quick way.
In the European Union for such orders an open competitive bidding is required, thus an option for further vehicles, that can later on be purchased without a new open competitive bidding is often contracted, at least in Germany. I don't know if the UK actaully kept to that European law.

Yet another reason to order less reliable T68A instead of flexity swift might simply have been because at date of the order, they simply did not yet know flexity swift would be much more reliable and less expensive to run.
Reliability is not something you can read from a datasheet.

All of these are out of scope of simutrans.

[Vladki]

The more I study about the UK trams the more questions appear. About intro/retire years. There seem to be two different candidate dates for introduction: when the production started, and when they entered service. At least in two cases: midlands T-69 and edinburgh CAF3, production started 3-4 years before they entered service (probably because the network was still under construction). Also about retire dates - should it be set, when replacement trams are introduced at the same network, or when other generally available tram is introduced? I would be in favor of the first.

[Freahk]

There seem to be two different candidate dates for introduction: when the production started, and when they entered service.

Imho when the first unit was accredited.
However, that information is often hard to find, so we might guess it.

Also about retire dates - should it be set, when replacement trams are introduced at the same network

Imho when actually replacement started in the real-world.
E.g. I would not retire Düwag supertrams when Stadler Citylink were introduces as they are not meant to replace the Düwag trams.

[Vladki]

What you mean by accredited?

Looking at croydon variobahn, and found a bit contradictive information:
https://en.wikipedia.org/wiki/Variobahn#Variobahn_trams_for_Croydon_Tramlink
length 32 m, 72 seats, 134 standing, 8x45 kW (maybe), 80 km/h, weight not specified

http://www.strassenbahn-online.de/Betriebshof/LF100/Variobahn_Technische_Daten/index.html
lenght 32.37 m, 84+128, 8x 45 kW, 41.8 t, 70 km/h

[Freahk]

What you mean by accredited?

"granted authorisation to run" might be better.

Looking at croydon variobahn, and found a bit contradictive information:

Both don't seem to be specific to Croydon Variobahn. Variobahn is a platform, so there are many variants that differ.
I'll need to investigate that.

Edit: Both sources are wrong in some points.
I just found an official announcement from Stadler: https://www.stadlerrail.com/media/pdf/2013_0821_medienmitteilung_auftrag_london_tramlink_gb_en.pdf

The bidirectional vehicles
have 72 seats and standing room for 134 passengers, and can reach a maximum speed of
80 km/h. The Variobahn is 32,370 millimetres long and 2,650 millimetres wide.

[Vladki]

Could you find acceleration data for variobahn or bombardier incentro?

[Freahk]

Yep,
According to this sheet from Bombardier it is 1.2 m/s² acceleration, 1.5 m/s² or 2.5 m/s² ermergency braking.

Could not finy acceleration data for Stadler Variobahn but I'd asume 1.2 m/s² either. Nowdays it's usually not a problem to build trams that accelerate even faster, but it's quite unusual to protect standing passengers.

However, while searching, I found their purchase costs https://www.stadlerrail.com/media/pdf/2011_0905_medienmitteilung_stadler_gewinnt_in_london_croydon_gb_de.pdf

Stadler Rail hat einen Auftrag der "Transport for London" für sechs neue Strassenbahnen
erhalten. Dies ist der erste Auftrag aus Grossbritannien. Der Vertrag wurde Ende August
unterschrieben. Der Auftragswert beträgt EURO 18,5 Mio..

In short: They ordered 6 Variobahns for 18.5m €. ~3.1m € each

I just find everything I'm not looking for...
See this interessting detailled report about citylink platform. https://www.applrguk.co.uk/media/files/LR-Applrg-Stadler-Sheffield-Tramtrain-25-May-2016pdf
Page 19 is specifically about Sheffield CityLink:
Service max. speed 100 km/h
Design max. speed 110 km/h
Max. acceleration 1,15 m/s2
Service brake 1,2 m/s2
Seats/folding seats 96/8

[Vladki]

Pushed  further fixes to https://github.com/vladki77/simutrans-pak128.britain

Could not finy acceleration data for Stadler Variobahn but I'd asume 1.2 m/s² either.

Yeah I assumed variobahn will have practically the same specs as incentro.
Should look at loading times too - variobahn has only 4 doors, incentro 6....

In short: They ordered 6 Variobahns for 18.5m €. ~3.1m € each

https://www.railwaygazette.com/bergen-car-order/32772.article
bergen announced €35m contract ordering 12 Variobahn trams = 2.9m EUR each
Variobahn for bergen was the same as for london.

Page 19 is specifically about Sheffield CityLink:

We already had most of it, so I just reallocated the seating to fit the real situation. In general I'm not counting foldable seats (klappsitze).
It is also one thing that is not consistently reported in specs...

[Freahk]

bergen announced €35m contract ordering 12 Variobahn trams = 2.9m EUR each
Variobahn for bergen was the same as for london.

That does not mean they cost the same! Trams are not something you can find in a supermarket with a fixed price put on it.There are many more factors involved than just the vehicle you order, one of them being the number of vehicles you order, as there are always some fixed costs involved in testing vehicles and getting authorisation to run these.

We already had most of it

Most of it, but a reliable source is always worth a lot. Note the mentioned capability for 110 km/h.
Now we got a reasonably reliable source for that number.

[Vladki]

Nowdays it's usually not a problem to build trams that accelerate even faster, but it's quite unusual to protect standing passengers.

That's good point. Modern trams seem to have acceleration in range 1.2 - 1.3.   We could use that to at least limit the old ones to not accelerate faster.

Service max. speed 100 km/h
Design max. speed 110 km/h

Do you think the limit 100 is due to tracks? And we should set 110 in dat?

I found interesting study about acceleration https://link.springer.com/article/10.1007/s40864-015-0012-y

It confirms the above values as being the approximate comfort limit. With emergency brakes above 2.5 will take you out of your seat.

They also note jerk (m/s^3) as important part of comfort.
Also they have acceleration values for some British rail vehicles.

I read somewhere a story about the first Czech tram demonstration by ing. Křižík (1891) that the mayor of Prague wanted to try driving the tram. He was allowed to. He pushed the controller to max, causing all the official guests to fall. So even the first trams were capable of high acceleration, or at least high jerk...

[Freahk]

Do you think the limit 100 is due to tracks? And we should set 110 in dat?

It might be the track or something else. In any case, I guess it's some decision to save money rather than a technical limitation of the vehicle.
I don't know of any tram train operating faster than 100 km/h mostly because faster speeds won't make a niticeable difference in ourney times due to the rather small power, thus low acceleration at high speeds and short distances between stops.

I read somewhere a story about the first Czech tram demonstration by ing. Křižík (1891) that the mayor of Prague wanted to try driving the tram. He was allowed to. He pushed the controller to max, causing all the official guests to fall. So even the first trams were capable of high acceleration, or at least high jerk...

I was allowed to drive the old "DUEWAG Großraumwagen TW 5103" from 1988 in a tram museum near Hannover and can confirm these old trams had an acceleration I have never felt in any modern vehicle.
The technical limitation, however is not the tractive effort itself but slipping.

[Vladki]

I think the feeling is more about jerk, i.e. difference in acceleration, then acceleration alone.

But I think that we cannot blindly follow the acceleration figures. I think that modern trams (21st century) with all their computer controls, might have applied limits on acceleration to be within the comfortable zone. The question is, how they behave when accelerating uphill. Is the controller smart enough to allow more tractive effort to cope with the hill?

For wheelslip we can go easy - the static friction coefficient for steel-steel is 0.15. So we can just multiply axle load with this.

[Freahk]

But I think that we cannot blindly follow the acceleration figures. I think that modern trams (21st century) with all their computer controls, might have applied limits on acceleration to be within the comfortable zone.

I am not quite sure about this but even if that applied, we won't be able to simulate a "maximum acceleration" cap in simutrans in any way.
So either we use the maximum tractive force that vehicle can actually produce without any caps to the acceleration, which will cause too fast accelerations on flat grounds, or we calculate force from the specified acceleration, which will give us too slow acceleration uphill.

I'd rather prefer the latter for the follwoing reasons:
1. it's near-impossible to find data about the maximum force of tram vehicles.
2. Trams accelerate to their rated speeed* within a single tile, so on slopes they usually will operate as constant-power instead of constant-force machines anyway.

*not sure if rated speed is the proper english term for the speed where a vehicle will switch from constant-force to constant-power.

For wheelslip we can go easy - the static friction coefficient for steel-steel is 0.15. So we can just multiply axle load with this.

If it was that easy... It depends on the axle load on powered axles. Assuming all axles have the same axle load might be a fair, slightly underestimated guess for most trams.

[Vladki]

Of course for tractive force we must count only powered axles' load (which we do not know exactly).
For braking force we can assume all axles braked, and thus just count total. I'll check if that is not already in code as default.
But counting that I get a problem. E.g. T68
acceleration and decceleration is same: 1.3 m/s^2 * weight 49 t = 63.7 kN braking or tractive force
for braking - all axles: weight 49 t * g * 0.15 (friction factor) = 72 kN friction force - OK
4/6 axles powered, so for acceleration we can assume 32-33t ?
1.3 m/s^2 * 33 t = 42.5 kN friction force, less than what is needed for such acceleration
If we want to achieve 63.7 kN on 4 axles, we need to get 43.3 t on powered axles and only 6 t on the unpowered central bogie...
How much could the engines weight in comparison with the rest of tram?

Found some info: https://otik.zcu.cz/bitstream/11025/14193/1/BP%2Bprilohy_Dudek.pdf
TE 022 - 40 kW DC engine used in Czech trams (Tatra K2, T3) has 340 kg...
TE 015 - 315 kW DC engine has 1750 kg used in diesel-electric locos...

TAM  1057  C6 - 300 kW asynchronous engine for trains has 830 kg
Further async motors: 340 kW = 775 kg; 500 kW = 1200 kg; 1280 kW = 2300 kg; 1600 kW = 2480 kg
ATM 090 - 90 kW async motor for trams has 320 kg; others: 65 kW = 300 kg; 170 kW = 660 kg

Synchronous motors with permanent magnets: 46 kW = 252 kg

So we can assume that async motors have 1/2 weight of DC motors of the same power.
Given the above examples, engine in t68 could have 600-900 kg.
Async engine in t68A maybe 400-500 kg. So wight difference between the two can be 1-2 tons.
But back to axle load - engines are just 5-7 % of the T68 wieght. That's not enough to significantly offset more traction on powered wheels

Edit: checking the code for defaults. Default deceleration for trains is assumed 0.5 m/s^2, for trams 1 m/s^2. Physical maximum for rail is 0.15*g = 1.47 m/s^2.   See convoy.cc, constants. BR_TRAM, BR_TRACK

[Freahk]

We cannot reliably calculate how much axle load is put on each individual axle, there are too many factors we don't know.
The position of boxies is just as important as the distributon of weight along the car, we know neither of them preciesely enough to calculate the load on powered axles preciesely enough, so we should simply put reasonable guesses.
Manufacturers are not stupid, so they will try to get more weight on powered axles than on unpowered axles but that only works up to some point...

For T68, we know from some source that roughly 70% of their total weight is on powered axles, which means there is ~17% more weight on powered axled compared to the weight on unpowered axles.
I'd say that simply asuming 10-25% is fine. We cannot calculate it more preciesely with the given data anyway...

Your assumed friction factor of 0.15 "steel on steel" might simply be wrong, in some cases even irrelevant.
My investigations resulted in a wheel on track friction factor of 0.3 on dry tracks.
Wet tracks will reduce that factor to 0.08-0.15 which can, however be increased by sand. In case of braking the wheel on track friction factor might not even matter, depending on the type of brake.

Edit: Sorry, I forgot to link my sources and couldn't find them again afterward -.-
Wiki states even greater values

For steel on steel, the coefficient of friction can be as high as 0.78, under laboratory conditions, but typically on railways it is between 0.35 and 0.5,[4] whilst under extreme conditions it can fall to as low as 0.05.

https://en.wikipedia.org/wiki/Adhesion_railway