The Tokyo to Osaka Line #6: Addenda

The Tokyo to Osaka Line #6: Addenda

Following the publication of the five parts of the The Tokyo to Osaka Line covering the classic railway route and the Tōkaidō Shinkansen, follow ups were drafted. Largely completed with technical stuff and other gems on the New Tōkaidō Line, as well as its drivers and engineers etc. In other words other aspects of the Tōkaidō Shinkansen which is so little known to the English speaking world! However due to numerous problems with the blog these drafts never got to publication stage. The date given above was the last any work had been done on these unpublished Shinkansen instalments.

Noise & air pressure issues with tunnels

As the above picture shows, despite the line’s high speeds the Bentenyama tunnel and others on the Tōkaidō Shinkansen are not really designed to mitigate the enormous air pressures that arises as a result of high speed trains entering the portals and creating a shock wave. It was thought in those early days the aerodynamics of the new trains would do the job but that was not to be.

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Series 0 front aerodynamic shape not that effective. And its why a train’s front fairing has got longer and more squat! Source: Conforg

It may come as a surprise to many to learn the New Tōkaidō Line had considerable in depth research into the noise effects generate by passing through tunnels, however this was done in terms of the passengers inside the trains themselves. Little work was done to determine the effects outside of the trains. The number of complaints that soon arose forced the railway to act (and the authorities too into passing regulations prohibiting noise above certain levels and so on) which is why its become such a major part of building high speed railways.

Even though the prototypes had bullet noses, there were nevertheless complaints of great discomfort as the test trains entered the tunnels. Obviously there was a design problem in both the tunnels and the trains. One of the results was to seal the new trains so any sudden changes in air pressure would not be felt.

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Report on the pressure changes experienced in tunnels – comparing the results for both prototype and pre-production trains. Source: World Bank.

The train doors themselves were of airliner standard. They were swing plug and sealed absolutely tight when closed just as would be expected in an airliner. However there were still problems. The trains’ air conditioning needed fresh flows of air and that had to come from outside. What the engineers did was to build a system where suitably placed sensors on both the train and the trackside would work to automatically close the train’s air intake vents as one began its approach to a tunnel and then these sensors would reopen these vents once the train had exited the tunnel..

The other changes came with the new and fast faster Shinkansen stock of the late 20th century. The trains acquired much longer noses. These doubly mitigated the enormous air pressures the trains caused upon entering and exiting the tunnels by dispersing the air change over a greater distance. However that still wasn’t enough.

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It might look silly, but there is a serious science behind these extremely long train noses! This is the ALFA-X, the next generation of high speed trains, achieving a top speed of 400kmh (almost 250mph.) Its nose is 22m! Generally higher speeds mean longer noses until a means of devising a suitable fairing (or aerodynamic front) can be found. Source: Design Boom

Over time the front noses of the high speed trains have got more refined. For example it has been found the more the nose area is refined the less the train suffers a reaction from the ‘hit’ when it enters a tunnel. If one is on a train and it passes another one will probably notice the jerk as the air being pushed away from each train hits the other thus a longer nose helps to mitigate this.

Some people think this long train nose stuff is a bit silly, but its actually a serious matter. The railway operators wouldn’t want their passengers to suffer discomfort at any time, whether its passing another train or going through tunnels, nor would they want residents who live along the railway also making numerous complaints about noise (and sonic booms) from the trains. Thus a sheer amount of work has to be done to mitigate the problems.

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The latest trains on the Tōkaidō Shinkansen (the N700 and N700A) have hugely defined air resistance capabilities, however tests have shown further refinements were necessary, as shown in the new N700S design. The design is known as a dual supreme wing and clearly its aim is to scoop the air smoothly away from the train’s body as well as up and over it. Source: Niponica

In terms of the new dual supreme wing of the N700S, by looking at the picture of the ALFA-X prototype, one can see these dual supreme wings have been made even bigger. Clearly the increased size of this is because there will be greater amounts of air and shock-waves to mitigate. Even with a dynamic tunnel entrance there’s a limit to how much the amount of air being pushed in front of the train straight into the tunnel can be mitigated.

The newer sections of the Shinkansen were built with various styles of tunnel entrance designed to reduce considerably these effects such as tapering tunnel entrances, and more recently, designs in the portal that include an extended portion of tunnel bore out in the open where there are openings or other means of allowing the enormous pressures to expand as the train passes. On the very latest lines (such as those in Germany and China) the air dispersal structure is built as part of the tunnel entrances rather than an add on.

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Extended JRE tunnel hoods. Source: Schienenfahrzeugtagung

The Japanese are now researching new ways of retrofitting older tunnels with noise mitigation measures. One is to build an extended section with ducts (JRE calls these hoods) in order to extend the pressure wave envelope beyond the tunnel portals. Even the current Shinkansen tunnels that have been built with extended hoods still have some issues and additional research is being conducted to find new ways to further prevent the noise (the sonic boom for example) emanating out of the tunnel area, annoying people nearby as well as affecting the train itself too.

The front light on the new trains

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That cover was originally intended to be quite a strong source of light, a considerable warning light in fact, thus the dome was quite translucent. Many of the early pictures of the two prototype Tōkaidō Shinkansen trains show this very bright front light that was sported. It was called a Kozen front. Source: Blackcat

It was arranged that a bright front light showed at the head of the train and a bright red light at the tail of the train. When the train reversed the lights changed colours too. The change was achieved by means of a rotating mechanism showing either a white or a red light. The arrangement didn’t last very long though.

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Onlookers cheering the arrival of the B unit after a test trip – and its clear the train indeed sported a lit up front dome. Note there has already been some changes to the front skirt of the train – possibly to assist with snow on the tracks. This would carry over in to the production models. Source: Twitter

Here’s another image – this easily the best but there’s no means of embedding this as is often the norm with any Getty related stuff. It shows JNR chairman Shinji Sogō in the cab of the test train (this is the B unit by the way) what’s great about this photograph is the train’s huge illuminated front dome! Getty Images.

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The cover was said to be 9mm thick and made of milky acrylic. Source: SL Taki Blog

There were problems with the Kozen dome however. They got damaged easily due to the rather thin nature of the dome. The rotating mechanism was quite flimsy and caused problems. How it worked is it was rather like a rotating flag pole with a long sheet of red coloured perspex attached to it. When showing white (as in the image below) the red perspex would be positioned out of the way. When the train reversed and a red needed to be shown the pole rotated thus the red perspex became illuminated.

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The rotating mechanism for the red light in the dome housing. The red was a thin sheet of plastic and didn’t inspire confidence. Its clear the bright light was achieved by utilising a pair of headlights. No doubt the rear red light too would have been extremely bright!

By the time the speed record tests runs had begun on the New Tōkaidō line in 1963 the illuminated dome arrangement appears to have been discontinued and that is probably because it was seen as an inconvenience. In due course the translucent domes were substituted with more stronger ones, whilst the red warning lights were instead incorporated within the housing containing the train’s headlights. Overall that meant a simpler system also resulting in less maintenance.

The Hankyu Railway borrows the Shinkansen

In the fourth post of this series I mentioned that the Shinkansen actually opened for public services in early 1963 and rail enthusiasts took the opportunity to take their first ever ride on the new railway! This was actually a normal railway that used the Shinkansen’s tracks during 1963 whilst its own tracks were upgraded. Here’s the story…

The Hankyu Railway’s Kyoto main line between Oyamazaki and Kammaki was upgraded between April and December 1963. The Hankyu is one of Japan’s few standard gauge railway companies – and that proved an advantage when it came to borrowing the New Tōkaidō Line temporarily. The Hankyu’s old alignment ran near to or along the proposed Shinkansen route and it was agreed the Hankyu should be upgraded to a new alignment alongside the Shinkansen. The diverted route was in operation from April to December 1963.

A Hankyu Railway train on the Shinkansen while its own line (at left) is constructed.) Source: Nikkei.

The new high speed line was to take an elevated route between these stations and the Hankyu railway desired that its line should do the same. The company’s existing line was at ground level but at risk of subsidence from the construction of the Shinkansen. It was thought the new elevated route (a mix of embankment and viaduct) would actually help some way towards stabilising the area’s problematic geology which was causing the issues. That as well as providing a safety barrier for the new high speed railway.

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The Hankyu Railway borrowed the recently completed Shinkansen tracks for most of 1963 – whilst its own main line was diverted and upgraded. This picture from December 1963 shows one of its express units speeding along the New Tōkaidō Line! Source: Twitter

The Shinkansen tracks were first built and then the Hankyu’s services were moved on to the high speed railway temporarily whilst its own brand new parallel elevated route was completed.

Temporary station at Kammaki on the Shinkansen in 1963. Its been said on other blogs the signs do say something like ‘trains now running on the Shinkasen!’ Source: Nikkei.

Despite both lines sharing the same gauge, the Hankyu trains operated on a current of 1500v dc, thus the Shinkansen cantenary system was temporarily adapted with power coming from the Hankyu’s own substations.

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Rail enthusiasts enjoying an early ride on the Shinkansen in June 1963 – well over a year before high speed services began – thanks to the Hankyu Railway! I think the location in the above scene was about here (the area is completely built up now as Google Streets shows.) Source: AiduslG2.

In this view on Google Maps the Hankyu line is seen climbing up towards the level of the Tōkaidō Shinkansen. The above 1963 picture was taken a little further eastwards, evidenced by the electricity pylons. I think the temporary Kammaki station can just be made out in the distance.

Old news article showing how the Hankyu Railway joined its tracks to the Shinkansen during 1963. Source: Hatena Blog.

A 1963 view of the Tōkaidō Shinkansen in use as part of the Hankyu railway system! The train that is heading towards the photographer has just come up the temporary incline from the line’s old route which is to the right and far below – one overbridge across the old route can just be seen in the lower right hand corner. Source:

The above image is very interesting because it does not look like the location in question at all. If one looks at Google Streets for example there are no mountains in the vicinity at all. Well there are some but they are actually a long way off! There are a number of things that confirm the location as being at Kammaki. The photograph has possibly been taken from the temporary station there as there was a flight of steps to the station that afforded a sort of observation platform too. Evidently a very high quality telephoto lens has been used to capture this picture. No surprise really for even in those days Japan had some of the best cameras and optics in the world and it was perhaps around this time that photographers in other countries were beginning to savour the use of their excellent Canon and Nikon cameras – especially as the 1964 Olympics were just a year away. The result of this excellent shot is that the distance to the mountains in the background, actually some 18 miles (30 km) away, is compressed thus these do look like they are in the local vicinity. The telephoto was also necessary to capture the train at the right spot some distance from the photographer for this is the location where it has just come up the temporary connecting ramp from the old railway formation. In fact the OHLE on that ramp can be seen rising up towards the Shinkansen formation.

Map from 1970 showing the Hankyu’s line parallel to the New Tōkaidō Line. Source: Twitter.

This section is known as the Oyamasakai shared right of way and both Hankyu railway and the JNR’s Shinkansen share a common superstructure, OHLE masts and boundary fencing etc. It is rare that it is was originally a structure whose construction and subsequent maintenance was shared by both a private and a national railway system. JNR is now JR Central, a private company too.

Recent view of trains on both sections of the Oyamasakai shared route. Source: Australian Transport Discussion Board.

Continued in part seven.

Updated January 2023.

Other posts in the series:

The Tokaido Shinkansen (introduction)

The Tokyo to Osaka Line: A history #1

The Tokyo to Osaka Line: A history #2

The Tokyo to Osaka Line: A history #3

The Tokyo to Osaka Line: A history #4

The Tokyo to Osaka Line: A history #5

The last three (never published) are focused on specific aspects of the Tōkaidō Shinkansen:

The Tokyo to Osaka Line #6: Tunnels/Kozens/Hankyu

The Tokyo to Osaka Line #7: Freight/Depots/Viaducts

The Tokyo to Osaka Line #8: Dr. Yellow/Train Control