From Prof. Lewis Lesley:
See: https://bathtrams.uk/can-trams-deal-with-baths-hills-hill-climbing-capability-of-trams/Maximum hill climbing, and braking down hill is not dependent on vehicle weight but the number of driven axles and the control system used. The steepest tramway with only wheel/rail adhesion was in Montreal (14%), which the replacement buses could not manage in winter. As a number of you have pointed out Lisbon has 12% gradients with all axle powered trams, coping with in all weathers for over 100 years. Trams used to climb the steep hills of Bath until 1939. The steepest gradient in the UK is Sheffield 10%, with all powered axle trams operating up and down safely since 1995.
Kind regards,
Prof. Lewis Lesley BSc, AKC, PhD, CEng, FRSA, MICE, FCIT, MTPS
Dear All,Once you have measured the gradient, you can check against the steepest gradients trams operated purely on wheel/rail adhesion.Montreal (until 1966) 14%, Saarbruchen (until 1965) 13%, Lisbon (currently) 12%, Sheffield (currently) 10%. The only constraint is that all wheels have to be motored. It is a simple calculation to work on the available adhesion on specific gradients, available to overcome gravity (uphill) and braking (downhill). Trams will have additional (emergency) brakes to provide 0.3g braking rates on the level and so available for down hill application. Magnetic track brakes are the most usual additional system, with shoes magnetically attracted to the rails (friction shoe/rail) and enhancing the effective mass on wheels/rail.Lewis13.8% grades in Lisbon Portugal.
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From Clive Hinchcliffe:
I repeat yet again there are trams available that are rated for 12% in all weathers.
I have personal been on trams in Lisbon starting fully loaded in a rain storm on 1 in 6 hills that buses have problems with.
The correct driving technique coupled with traction control system can overcome any issues.
In some Swiss cities they have trams starting on 1 in 5 inclines in snow storms.
Coupled with the fact that trams used to operate in Bath I can foresee no issues.
Time to put this to bed until there is a full feasibility study…..Best wishes.
Clive Hinchliffe
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From David Walmsley
I asked a contact in Lisbon about gradients. He works for the public transport company Carris. He said the maximum gradient in Lisbon is 14.5 %, not counting funiculars, and the sharpest curve is 11m radius. And it works.
David Walmsley
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From Adrian Tuddenham – electrical engineer:
The big advantage of trams in ice and snow is that only the width of the
track surface ( 2 or three inches) needs to be completely cleared, not the whole road width.
This is something trams can easily be equipped to do for themselves; Bath
had a ‘snow broom’ car to keep the tracks clear (as did most cities with
trams).When the M.O.D. had an important base at Lansdown in the 1960s or ’70s,
it was considered vital that Lansdown Road was never allowed to become
impassable. Under-road heating pads were installed on the vulnerable
bits. I never heard of them being used and I don’t suppose anyone
remembers them now. They heated the whole width of the road, which was
very wasteful, and they were vulnerable to damage by movement of the
surface under heavy traffic.Compare that with trams, where only the rails need to be heated (if this
system is chosen) and traffic will not damage them. No special equipment
is needed under the road because the heating current can be passed
directly through the rails themselves.Adrian Tuddenham
Just to put the cat among the pigeons it seems it can be done and is done:
Interesting from Stadler“and to work on tracks with a maximum gradient of 10%.” (Sheffield)Alstom“In addition, the Citadis X05 for the Urban Community of Caen la Mer can climb slopes with gradients of up to 8% and has standardised, proven and more accessible components.”Skoda 15T(8.5%)In general, it advisable to minimize grades on any new transit system as much as possible. However, where necessary (to access critical sections of a city, to contain costs, or for other reasons), LRT can handle grades as steep as 12% (depending on vehicle design, motor power, and other technical capabilities). Here are some examples:
Europe
· Sheffield – short section on 10% grade, and others at 9%. Articulated tramcars operate without any problem on these grades, on a daily basis. All axles on the cars are powered to enable operation on such gradients.
· Würzburg – operation on approximately 10.8% grade. HeiterBlick tram https://www.heiterblick.de/en/
vehicles/ https://en.wikipedia.org/wiki/ Trams_in_W%C3%BCrzburg · Nordhausen – the tramway, located in this small city on the south side of the Harz hills range, negotiates a 9.8% grade in Stolberger Strasse for about 500 meters. Siemens Combino tram/train
USA
· Boston – C-Commonwealth Avenue streetcar line has a gradient of more than 8%.
· Portland – MAX LRT system has a 7% grade on the ramp leading from Second Avenue onto the Steel Bridge.
· Little Rock – River Rail streetcar line between Little Rock and North Little Rock climbs a gradient of 7.8% on the approach to the Main St. bridge over the Arkansas River.
· San Francisco – grades of 9% on the J-Church and L-Taraval streetcar lines of the Municipal Railway.
· Pittsburgh – Route 52-Arlington has a grade of 10%, routinely negotiated by modern Siemens and CAF articulated interurban-type railcars.
Regards
John Daglish
Paris, France
Sure they can handle steeper grades. 12% isn’t a problem. The issues come fast and furiously if the grade is above 5%. Nearly all STANDARD LRV’S MAX OUT AT 5% GRADES though, you can get specialized parts and systems for grades greater than 5% from nearly all manufacturers of LRV’s. The issue is at that point, your LRV is no longer STANDARD but now has specialized parts and systems. That means they cost more per vehicle than standard LRV’s do. At that point, city politicians the world over universally, loose their minds and political confidence.
Zwei Replies: I was told by chap who worked for Siemens back in the day, that the industry standard for new trams or LRV’s was 8% grades, which meant a tram with crush loading could stop and start on that grade.
If one’s tram route at grades greater than 8%, all axles must be powered as are the cars in Sheffield. Of course cities like Amsterdam and Den Hag, where the only grade waas climbing over a dike, could have cars with fewer motors than recommended.
From my investigations, the 5% grade limit in North America is based on heavy rail metros and R/T systems which like regular railways can only surmount modest grades. Vancouver streetcars saw had 9% grades on the Alma/Dunbar route and Montreal had 14% grades.
Parts of King Street have 8.5% -9% grades (current route 504 A), the old York Radial Route on Yonge Streetcar north of Hogg’s Hollow (between current Lawrence Ave. and Hwy. #401) was over 13% both sides of the hollow on Yonge St.
My point is unless it’s the cheapest price humanly possible, politicians complain and rant the world over. I have seen normally intelligent taxpayers seriously and openly propose that slave labor be used on all municipal projects, even to save a few million dollars. You would be surprised how sensitive voters are to costs.
I found this on line, I hope this proves helpful.
For well over a century, light rail transit cars (known historically as trolleys, streetcars, interurbans) have been able to negotiate much of the existing street and roadway infrastructure commonly encountered in urban settings, including grades as much as 14% and even higher.
Modern light rail vehicles – even the latest totally lowfloor models – are no exception. For climbing, traction is often assisted with sanding. For braking, modern LRVs are commonly equipped with three braking systems: disk brakes; dynamic brakes; and magnetic track brakes.
On several proposed surface routes for Austin, designing the light rail alignment to take advantage of this capability could eliminate the need for costly reconstruction of roadway infrastructure, such as on Guadalupe St. and South Congress Ave.
Several selected examples of modern light rail systems in the USA and Europe that have alignment sections with higher gradients:
• San Francisco: 9% grade (Siemens LRVs, on J Church line)
• Toronto: 8/10% grade (Bombardier/Alstom LRVs, on line 512, at Bathurst St. hill)
• Portland: 7% grade (Siemens Avanto S70 LRVs, at ramp onto Steel Bridge)
• Sheffield, UK: 9% and 10% grade (Siemens Supertram; Stadler Citylink LRVs)
• Caen, France: 8% grade (Alstom Citadis X05 LRVs)
• Würzburg, Germany: 10.8% grade (Alstom GT-N, HeiterBlick Artic LRVs)
• Nordhausen, Germany: 9.8% grade (Siemens Combino LRVs, at Stolberger Strasse)
I worked on the Tenerife island LRV system 2005-2007. The tramway climbs from sea level to 500 m of altitude over some 12 km. The steepest slope (and also the steepest station/stop) is at 8.7%. There is one straight slope of about 1 km with gradient 7-8%; you look down and see the ocean below… It was a very interesting project with some technical challenges