The International Simutrans Forum

 

Author Topic: Steam trams  (Read 3170 times)

0 Members and 1 Guest are viewing this topic.

Offline MCollett

  • *
  • Posts: 214
  • Languages: en
Steam trams
« on: September 11, 2013, 06:24:51 AM »
In the real world, electric trams were strongly preferred to steam trams from quite early on.  By the 1890s, any newly-built tram systems would almost certainly have been electric, and existing steam systems were being converted to electric.  But in pak128.Britain Exp. as it currently stands, steam trams are strongly competitive with electric, at least until 1899 and arguably right up until they become unavailable in 1902.   

So I wondered, where is the error?  Should steam trams be more expensive to run? Are they too powerful (the tractive effort does look rather high)? Or should electrification be cheaper?

Answer: none of the above.  In the current pak, steam trams have a maximum speed of 40 km/hr.  It seems that they were in fact legally required to be governed to a much lower speed, although there is some disagreement about what that speed was (it may have varied with time or even with place). Wikipedia says 12km/hr,  this picture caption says 8mph (13km/hr) and The Encyclopaedia of Plymouth History says 10mph (16km/hr).

Of course, that raises a different question.  If steam trams are so slow, why bother with them instead of horses?  And the answer to that, which opens a completely different can of worms, is that horses were in fact (a) even slower (perhaps only 5mph), and (b) significantly more expensive to run; neither of which are true in the pak at present.

Best wishes,
Matthew

Offline Junna

  • Devotee
  • *
  • Posts: 1081
Re: Steam trams
« Reply #1 on: September 11, 2013, 07:09:23 AM »
As far as I know other steam tram systems (some of which remained in operations very long) were allowed to run at higher speeds - the limit, in-fact, was imposed not by the mechanical qualities of the steam tram engines, but by vested interests of various sorts wanting to disfavour the use of steam trams in urban centres. The impact on horses was considered, for example, and they were regarded as unsightly and monstrous. This, more than any technical limitation, was behind the restrictions imposed upon the steam tram engines, and the primary reason that they were so unpopular in the UK (IIRC Milano tramways continued using a steam-powered tram engine until the mid-1950's on yet to be electrified routes).

The thing then is that the steam tram engine is not flawed by design, but by political superstructure, ergo we should not infringe too much on the creative liberties of the player to do as he/she sees fit, and leave it up to them.

The steam-tram in the game looks a lot like the GER G15 (later LNER Y6) tram engines, whose actual speed limit in operation was quite low due to the lower standard nature of the Wisbech and Upwell Tramway, but it is not impossible that 40km/h would have been possible to achieve.

Offline jamespetts gb

  • Simutrans-Extended project coordinator
  • Moderator
  • *
  • Posts: 18241
  • Cake baker
    • Bridgewater-Brunel
  • Languages: EN
Re: Steam trams
« Reply #2 on: September 11, 2013, 10:23:35 AM »
An interesting discussion - thank you. The costs are not currently properly balanced; steam operation should certainly cost rather more than electric operation once the player has invested in the necessary infrastructure for the electrification. Also, electric trams should be able to accelerate considerably better than steam trams. The latter should already be balanced; if the steam trams accelerate almost as well as the electric trams, they might need to be recalibrated. (Indeed, I recalibrated the power of all steam locomotives for Pak128.Britain-Ex 0.9.0, but I am wondering now whether I missed the steam tram locomotive).

Offline MCollett

  • *
  • Posts: 214
  • Languages: en
Re: Steam trams
« Reply #3 on: September 11, 2013, 11:19:33 AM »
The costs are not currently properly balanced; steam operation should certainly cost rather more than electric operation once the player has invested in the necessary infrastructure for the electrification.

Currently a steam tram with medium trailer costs 0.66+0.12 per km to run; a toastrack tram costs 0.42 per km to run, plus 64.00 per km per month for the electrification.  For the toastrack to be cheaper than steam, there must be at least 64.00/(0.76-0.42)=178 convoys over the track per month (i.e. about one every two minutes) which is absurdly frequent.  Even then, the steam tram is still actually better, since its capacity is higher (and can be made much higher with a large trailer for only fractionally higher cost).  The average speed of the two in operation is almost the same.

Best wishes,
Matthew

Offline MCollett

  • *
  • Posts: 214
  • Languages: en
Re: Steam trams
« Reply #4 on: September 11, 2013, 11:29:47 AM »
(IIRC Milano tramways continued using a steam-powered tram engine until the mid-1950's on yet to be electrified routes).
This article says you are right, but adds that they operated at the dare-devil speeds of 15km/hr in the countryside and 10km/hr in town -- not very different from the British limits.

Best wishes,
Matthew

Offline Junna

  • Devotee
  • *
  • Posts: 1081
Re: Steam trams
« Reply #5 on: September 11, 2013, 02:45:36 PM »
This article says you are right, but adds that they operated at the dare-devil speeds of 15km/hr in the countryside and 10km/hr in town -- not very different from the British limits.

Best wishes,
Matthew

It's worth mentioning that, by and large, the limits were similarly low for most electric trams as well, particularly early ones. Actual limits do not necessarily reflect the potential maximum speed - though they were troubled by poor acceleration, which obviously is a key in urban environments and constrained their usefulness.

I do think that the cost of the electrification ought perhaps to be made lower... The Wisbech and Upwell Tramway originally had a speed limit of 8mph (12km/h), but this was raised to 12 mph (19.1km/h) in 1904 (though I seem to recall mentions of the limit being regularly exceeded in practice). This restrictive speed limit was largely due to the low quality of the railway itself, built as it was to a lower standard. It would perhaps be interesting to know if any records exist of potential maximum speed on good track.

Offline jamespetts gb

  • Simutrans-Extended project coordinator
  • Moderator
  • *
  • Posts: 18241
  • Cake baker
    • Bridgewater-Brunel
  • Languages: EN
Re: Steam trams
« Reply #6 on: September 11, 2013, 04:52:27 PM »
The steam tram currently in the game looks rather more like this one from Birmingham. Unfortunately, I cannot find any technical statistics for this locomotive: I might have to consider buying this book.

I have for now adjusted the technical data of the steam tram locomotive to match the GER G15 Class, which I suspect is more powerful than the more usual types. However, that adjustment has resulted in a reduction in tractive effort from 35 to 26kN and the power from 60 to 40kW, as well as an increase in the weight from 10 to 21.6t, all of which should provide realistic impairment of the performance.

I am not in a position to do proper re-balancing at this stage, but I have as an interim measure increased the running cost from 66 to 88c/km. This should suffice for the time being.