More about Jo-Jo-han, the track, will in time apear here on this page.



1. Static railway switch

2. Traditional gear and minimum station distance

3. 250 km/h over the motorway?

4. ERTMS European Rail Traffic Management System

5. Track width

6. Induction instead of over head lines

7. Distance between stations and short travel

1. Static railway switch

The distance between counter-gears (one track is divided into two tracks), ie how close you can place side tracks out of the main track, affects how close it can be between stations. From a safety point of view, we have chosen that vehicles that are to take the siding in a static switch should be a single vehicle, disconnected from other vehicles. Since the knowledge of the desire for the vehicle to take the siding is known in good time, this decoupling (undocking) does not need to be done time-critically, and can take place as soon as possible after passing the immediately preceding reverse gear.

The activity to be performed in the vehicle is that extra wheel axles, one at the front and one at the rear, should be folded/pushed down a distance of 5 - 10 centimeters and then locked in the lower position. Each wheel axle carries four wheels. The wheels have no drive and no braking function. They are so-called freewheels. The consequence is that the mass of the wheel axle plus wheels is not deterrent, probably a couple of hundred kilos. How long time must be set aside to safely perform the level lowering of the wheel axles? A few seconds should be enough. With the possibility to repeat the requested, but unsuccessful action, maybe 10 seconds. I have chosen 15 seconds as the time limit. At a speed of 250 kilometers per hour, a shuttle travels about one kilometer in 15 seconds. My conclusion is that we can have down to one kilometer between reverse gears on the main line.

There is no need to place stations so close for either travelers or goods. However, it is conceivable that at some odd point there may be a need to place switches for passenger shuttles and cargo shuttles so close to each other. For several consecutive side tracks for cargo shuttles, it is possible, but probably very rare, to see a need for counter-gears at a distance of less than 10 kilometers. For travelers, the distance between departures to stations is also rarely less than ten kilometers. Not even with 100 stations along the main line Stockholm - Gothenburg/Malmö, the distance between stations for travelers will be so short. Technology is not the limitation, but it provides opportunities that are significantly better than the actual need.

3. 250 km/h above a motorway?

A publication from the Swedish Transport Administration states that a Swedish motorway, with a good standard and with a maximum speed of 110 kilometers per hour, must have a minimum horizontal curve radius of 1,200 meters. For the Jo-Jo train and shuttles, the maximum speed is 250 kilometers per hour. With a 200 millimeter cant (dosage, skew) we get a minimum curve radius of 1,800 meters. This applies provided that we have a lateral acceleration of less than 1.5 m/s2 and that we use anti-roll suspension. More lateral acceleration means that passengers cannot move freely on the train. Anti-roll suspension is a well-established technology that prevents the side acceleration from tilting the vehicle. The suspension in the outer curve is made stiffer. The vehicle is straight on the track. If we also use active basket inclination, we can drive 15% faster in the curve without the side acceleration increasing (gives the same effect as a larger dosage). With basket inclination, we get the Jo-Jo train's smallest curve radius down to 1,320 meters. Very close to the smallest curve radius on the highway. To cope with even smaller curve radii, eg the 1,200 meters, we can take a short cut in the curve. How much we can do this depends on the length of the curve. If the turn is less than 25 degrees, we can stay over the motorway itself (normal width 21.5 meters). The motorway corridor is 70 meters wide. If we use that entire width to obstruct the radius of the 1,200 meter curve, we can manage a turn of 65 degrees. Should we occasionally have sharper curves than that, well then the Jo-Jo train speed must be reduced below 250 kilometers per hour or the dosage be more than 200 millimeter.

Vertical curves. The Swedish Transport Administration states that for motorways, a convex curve (hilltop) may have a vertical minimum radius of 16,000 meters and a concave curve (valley) of at least 5,500 meters. For railway vehicles, a vertical acceleration of a maximum of 0.3 m/s2 is specified. The convex curve can handle the Jo-Jo train at 250 kilometers per hour, but to cope with the concave curve, the pillars of the bridge deck must be made higher to increase the radius of curvature (reduce the valley). It increases the cost, but only marginally. The combination of deep valley and narrow curve is not technically insoluble, but entails higher costs. The lateral forces at high track and sharp turns require stronger pillars under the bridge.

4. ERTMS European Rail Trafic System

ERTMS is available in different basic versions 1, 2 and 3. Sweden has chosen version 2. Version 2 is more expensive to install and maintain than version 3. But version 2 has been in more extensive practical operation. Cut out from Wikipedia: "Version 3 includes features for higher capacity, including more frequent train operations and the possibility of another radio system instead of GSM-R." Version 3 thus allows us to, for example, use 5G for communication between the Power Shuttle, command center and other shuttles on the track. Of course, it is especially valuable with fast communication in connection with docking, and shuttle entry on the main line. When platooning (driving with a truck convoy) you use wi-fi and the same technology should also be applicable for the Jo-Jo train.

GSM-R is already developed throughout Sweden and coverage is ensured by the system working even if every second base station were knocked out. 

So-called Eurobalises are deployed on the track. These have fixed information, for example about their location, about the track's properties later on. The balises get their energy from the train that passes over it and then it responds by transmitting the information to the train that sends information on to the command center. The Swedish ATC2 system also has similar balises. However, they have a fairly limited memory capacity. The Eurobalises also have plenty of capacity available for future development - such as Jo-Jo trains.

ERTMS version 3 provides the opportunity to run the trains closely in succession. The so-called block section is not a fixed installation in the track, but an adjustable electronic quantity that surrounds the train. It provides the opportunity for linear docking.

5. Distance between rails

Normal track gauge is measured as the distance between rails. They are measured 14 mm below the top edge of the rails (Rail top). The standard value is 1435 mm, but it is allowed to be down to 1430 mm and up to 1470 mm before it needs to be adjusted. In simpler terms, the center distance between rails is 1.5 meters. The railway wheel has a flat roller path and on the inside of the rails the wheel has a flange. The transition between the flat roller path and the flange is not sharp, but is curved with a slow transition between roller path and flange. The finesse of this is that if the railway vehicle tends to move e.g. to the right of the track, the wheels on the right side with their curved surface will start to "climb" up on the rails. There on the curved surface, the circumference of the wheel is larger and the wheel thus automatically steers the railway vehicle back towards the middle between the rails. This function is independent of the track gauge. If you increase the track width while maintaining the distance between the wheels, the impact effect will not be so strong. There is a discussion about increasing the nominal dimension 1435 to 1437 millimeters. The advantage would then be that at high speeds the so-called sinus movement would be smaller on long straight stretches of the track.

Risc to turn over. Railway vehicles have a so-called load profile. It indicates e.g. the maximum height and width of the vehicle. In Sweden, we have a load profile: A 3,40 m wide and 4,65 m high, B 3,40 m wide and 4,30 m high and C 3,60 m wide and 4,83 m high. Or simpler, generalized; 3,5 m width and 4,5 m height. To get a low center of gravity, the ratio of height over width should be as small as possible 4,5 / 3,5 about 1,3 (This is a simplified way of looking at the matter, of course knowledge of the actual central of gravity above the base surface is preferable, but it is not readily available). In order to have a stable function, the support surface must be as wide as possible, the ratio of vehicle width relative to track gauge must be as small as possible 3,5 / 1,5 gives approximately 2,3. The product between the relative height of the center of gravity 1,3 and the relative value of the support surface 2,3 then becomes a typical roll risk value of 3. Let us compare with a passenger car. We then choose an SUV that is significantly more prone to overturning than a sports car. Values ​​for the Volvo XC90, height width ratio = relative center of gravity height 0,92 and the relative support value of the support surface close to 1 (the wheels placed as far to the side as possible). The inherent risc to overturn is three times larger for the train. If we made the comparison with a race car, the difference would obviously be even worse for the railway vehicle. Vehicles that stay on the "right keel" in an accident cause considerably less damage to their passengers, so low center of gravity and wide base are always preferable.

The reason for the large load profile is of course the desire for the opportunity to take large loads. The gauge was early so-called narrow gauge (narrow gauge is less expensive to build). As the state took over the railway in the Sweden, we now have a normal width of 1.5 m (Exception of Stockholm's local traffic operated Roslagsbana with just under 0.9 m between rails). Changing the existing railway network to something more technically sensible is not economically reasonable. Not only tracks but also the fleet must be changed.

A larger track gauge is safer.  For a completely separate new railway, which requires vehicles with extra wheel axles for the gear unit without moving parts, the situation is different. Here we have the chance to develop technology that is significantly safer than what we have today. As for the car, we can choose a track gauge that corresponds more close to the vehicle width, e.g. for railway vehicles 3 meters between rails instead of 1,5 meters. The risk of overturning is minimized. We can choose an optimal load profile. And not least valuable, the technology for suspension will be simpler, cheaper and more robust. Finally, we can have a larger cant elevation in horizontal curves. We can easily drive on a bridge over a motorway, probably without active tilting. Note in particular that on Jo-Jo-han all trains run on the main track constantly with a very small speed variation, only +-5 km/h. We get a smooth flow and the track can be optimized for the speed of 245 km/h. Optimal and unbeatable comfort for the traveler.

6. Energy to the train via induction instead of via overhead contact line

With induction, you can transfer energy without contact. When building a completely new railway with also completely new vehicles, we can choose to replace the currently common overhead lines with an inductive power supply for the Jo-Jo train.

Traditionally, trains have been pulled by locomotives. Heavy units with a very powerful engine. Other parts of the train were carriages without their own engine and driving ability. Electrification of the railway did not change this, but today we see more and more so-called motor trains where more or all units in the train have their own driving capacity. However, trains today often consist of a fixed combined unit of e.g. two or more motor vehicles with one or more non-motorized vehicles. A train set can e.g. consist of four permanently connected units. If more capacity is needed, you connect to a similar train set of four units. Each such train set has its own pantograph (often also one in reserve), which receives power from the overhead contact line. Trains with high top speeds have more advanced and expensive overhead lines. The cost picture is in the range of SEK 10 to 40 million per kilometer. A modern overhead contact line can transmit 1000 amperes. With 15 kV voltage, the transmission can reach a power of 15 MW. With smart technology, the carbon rail on the pantograph can wear slowly, but unfortunately errors occur in the system from time to time. Wear, sparking e.g. due to frost or rain gives pitting and sometimes the contact wire also wears out or down. Repair or replacement is costly and in the meantime prevents traffic on the track. So-called motor trains stress the track less (no heavy locomotive) and provide the opportunity for faster acceleration thanks to more driving wheels.

Induction is the physical phenomenon that in a transformer transfers energy from the primary coil to the secondary coil. It is thus conceivable that primary coils are built into the track under the train and that secondary coils in the train absorb energy. Such technology is being tested for power supply of vehicles on the road. Tests are also performed with a overhead contact line and with rails in or on the road. In these tests for speeds up to 100 km/h, ie considerably slower than the Jo-Jo train, different systems are thus tested in competition. It should be possible to conclude that the cost of inductive energy transmission at higher speeds can be more cost-effective (less investment and no wear) than overhead lines. The position of the train in the side is carefully determined by the rails and the distance between the primary and secondary coils can be made relatively small. It should be significantly more efficient than induction for vehicles on the road.

For the Jo-Jo train, inductive power transmission would mean that all shuttles get power that way both for propulsion and heat etc. of the shuttle, even for shuttles docked in the Jo-Jo train. The power shuttle could possibly be discontinued and the more powerful energy distribution via coarse lines in the automatic coupler could be reduced or eliminated. Battery operation could continue to be an option on connecting runways, but induction here too would reduce the dead weight of the shuttles. Without batteries, the spare track would also need to have inductive transmission installed. A smaller energy supply in batteries would, however, give a redundancy in the event of short-term problems with supply via induction. These batteries could also be used in combination with supercapacitors for energy recovery during braking.

An additional advantage of avoiding overhead lines and pantographs is to avoid the noise they give rise to. Without overhead lines with associated poles etc., the facility becomes more aesthetic. It should be possible to lower the required height in train tunnels and thus the cost to make tunnels. Air gap around trains in the tunnel is needed, but that function is largely met thanks to the spare track.


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Topics to be handled, described.

Ranger yards

Maintenance courses

ERTMSL3 - wires

Train line


Station locations - different options

Step by step in operation - suggestions for stages

Build on pillars / bridge / viaduct

Prefabricated parts

Individual bridge for each single rail


  • Main track
  • Spare track
  • Loops
  • Connection tracks
  • Feeding tracks
  • Capillary tracks