test: realistic tractive effort and freighttrains feature w.

[michael blunck]

Just out of curiosity I wasted some time to test the patch´s new "freighttrains"
feature together with "property 1F" (set tractive effort) and the DB set
locomotives.

The proving ground has been a most steep grade (from level 1 to level 15). An
auxiliary station immediately at the foot of the grade caused the test train to
stop before beginning to climb the grade.

The smallest "low board" wagon from the DB set XL which carries 15 tons of coal
acted as a test wagon. By using the "freighttrains" default value of "5" its
capacity resulted to a "mock weight" of 75 tons.

A train passed the test if reaching the flat track behind the grade with its
full length, and it´s lowest speed on the grade is recorded then. If the train´s
velocity decreased to 1 km/h while being on the grade the test has been failed.

Steamers which need tenders have been added them for the test.

Now, here are the results (P = passenger -, F = freight - , U = Universal
locomotive):

Steam
Name Type Wagons resulting Speed [km/h]

BR92 U 2 17
BR38 U 2 20
BR18 P 2 24
BR01 U 2 37
BR45 F 3 35

Diesel
Name Type Wagons resulting Speed

V140 U 2 28
V200 U 4 32
V100 U 3 20
V160 U 4 56
BR232 F 8 32
"Tiger" F 10 28

Electric
Name Type Wagons resulting Speed

BR175 U 4 24
BR195 F 6 28
BR144 U 4 25
BR194 F 7 24
BR140 U 5 48
BR150 F 8 49
BR110 P 5 45
BR103 P 6 59
BR250 F 7 65
BR181 P 5 43
BR120 U 7 37
BR112 P 5 37
BR101 U 6 72
BR182 U 6 74

What can be seen from the test?

Well, firstly, steam engines are *very* weak. This is due to their low "adhesive
weight". E.g. the BR01 has a total weight of 114 Mp but its adhesive weight is
only 60 Mp. This is corresponding to the axle scheme 2'C1'. OTOH the BR92 has a
weight of 57 Mp which is identical to its adhesive weight (because there are no
non-powered axles). This enables to pull a comparable load as the BR38, althoigh
the BR 92 has a power of 588 kW but the BR38 has 868 kW.

Also, it seems that steam engines do not reach the usual µ = 0.3 (friction
steel/steel) but have a slightly lesser µ of 0.25 ... 0.273 (BR45).

Heavy (and usually slower) 6-axle diesel and electric engines are far superior.
Even lighter 4-axle (passenger) locomotives aren´t as bad because their built-in
"slip control" causes a better use of the available tractive effort.

I´ll release a DB Set XL update including "property 1F" as soon as tractive
effort data for the railcars will be available (or not ).

regards
Michael

[Daan Krantz]

Hmm interesting, I had tested it a bit, and indeed there is defenately
some need for a calback on this feature .
Anyway I'm still a bit unsure in the way steam engines are compared now.
For example the pasenger trains had gigantic wheels resulting in a realy
high topspeed while the wheight it could get moving form 0 was pretty
low compared to freight trains with much smaller wheels.
this diferense between topspeed and traction (is that the right term?)
isnt well displayed now. But exactly that was the diferense between a
pasnger train and a goods train.

hmm sory I can't realy explain what I'm trying to tell. BTW this
discusion has been on http://www.tt-forums.net to:
http://www.tt-forums.net/viewtopic.php?t=6403
Anyway sofar I like the results ,

Daan


Michael Blunck wrote:

Just out of curiosity I wasted some time to test the patch´s new "freighttrains"
feature together with "property 1F" (set tractive effort) and the DB set
locomotives.

The proving ground has been a most steep grade (from level 1 to level 15). An
auxiliary station immediately at the foot of the grade caused the test train to
stop before beginning to climb the grade.

The smallest "low board" wagon from the DB set XL which carries 15 tons of coal
acted as a test wagon. By using the "freighttrains" default value of "5" its
capacity resulted to a "mock weight" of 75 tons.

A train passed the test if reaching the flat track behind the grade with its
full length, and it´s lowest speed on the grade is recorded then. If the train´s
velocity decreased to 1 km/h while being on the grade the test has been failed.

Steamers which need tenders have been added them for the test.

Now, here are the results (P = passenger -, F = freight - , U = Universal
locomotive):

Steam
Name Type Wagons resulting Speed [km/h]

BR92 U 2 17
BR38 U 2 20
BR18 P 2 24
BR01 U 2 37
BR45 F 3 35

Diesel
Name Type Wagons resulting Speed

V140 U 2 28
V200 U 4 32
V100 U 3 20
V160 U 4 56
BR232 F 8 32
"Tiger" F 10 28

Electric
Name Type Wagons resulting Speed

BR175 U 4 24
BR195 F 6 28
BR144 U 4 25
BR194 F 7 24
BR140 U 5 48
BR150 F 8 49
BR110 P 5 45
BR103 P 6 59
BR250 F 7 65
BR181 P 5 43
BR120 U 7 37
BR112 P 5 37
BR101 U 6 72
BR182 U 6 74

What can be seen from the test?

Well, firstly, steam engines are *very* weak. This is due to their low "adhesive
weight". E.g. the BR01 has a total weight of 114 Mp but its adhesive weight is
only 60 Mp. This is corresponding to the axle scheme 2'C1'. OTOH the BR92 has a
weight of 57 Mp which is identical to its adhesive weight (because there are no
non-powered axles). This enables to pull a comparable load as the BR38, althoigh
the BR 92 has a power of 588 kW but the BR38 has 868 kW.

Also, it seems that steam engines do not reach the usual µ = 0.3 (friction
steel/steel) but have a slightly lesser µ of 0.25 ... 0.273 (BR45).

Heavy (and usually slower) 6-axle diesel and electric engines are far superior.
Even lighter 4-axle (passenger) locomotives aren´t as bad because their built-in
"slip control" causes a better use of the available tractive effort.

I´ll release a DB Set XL update including "property 1F" as soon as tractive
effort data for the railcars will be available (or not ).

regards
Michael

[Patchman]

Daan Krantz wrote on Sat, 03 Apr 2004 22:45:26 +0200:

Hmm interesting, I had tested it a bit, and indeed there is defenately
some need for a calback on this feature .

Why? The data seemed to make sense to me...

Anyway I'm still a bit unsure in the way steam engines are compared now.
For example the pasenger trains had gigantic wheels resulting in a realy
high topspeed while the wheight it could get moving form 0 was pretty
low compared to freight trains with much smaller wheels.
this diferense between topspeed and traction (is that the right term?)
isnt well displayed now. But exactly that was the diferense between a
pasnger train and a goods train.

Well, that's what the new property 1F is for, it allows you to set the
maximum force the engine can generate from start, as a fraction of its
total weight.

--
Josef Drexler | http://publish.uwo.ca/~jdrexler/
---------------------------------+---------------------------------------
Please help Conserve Gravity | Email address is *valid*.
Give up downhill skiing. | Don't remove the "nospam" part.