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Grand Tour de Öffentliche Verkehrsmittel Recap – Part Two

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Total Distance in km5,519
Total Elevation in m21,111
Total Amount of newly ridden kms from wandrer.earth2,225 (~40 % of total kms)
Number of Stages with company9
Number of Stages visiting friends6
Number of punctures2 – both for Nick in Stage 50

After my personal high- and lowlights from cycling the 59 Stages of the Grand Tour de Öffentliche Verkehrsmittel in Part One of this recap, it’s now time to look into the public transport network in more detail. Who doesn’t like a great public transport map? Plus, very importantly – some insights from how I managed my blood glucose during the whole Grand Tour.

Historical Look at the U-Bahn and S-Bahn Network

While researching the history of the stations along the U- and S-Bahn lines, my interest in the naming and changes of these train lines was piqued. The Berlin underground train system was the first to be opened in Germany in the year 1902 and increased since then to become the largest underground system in German-speaking areas. The S-Bahn lines, which run on the regional train tracks and are operated by a different company to the U-Bahn, joined the Berlin public transport network in 1913 once the train tracks switched from steam to electrical power.

The U- and S-Bahn routes of Berlin from its beginnings to 2020 – Click on it, to open in a new tab!

Since then, Berlin has been through a lot – two World Wars and more recently the Cold War, where Berlin was divided into West and East Berlin. I wanted to display how Berlin’s history played out through its public transport network so I created the gif showing the evolution of the U- and S-Bahn lines from their beginnings until 2020 in 5 year intervals. This would give an indication of how mobility of Berliners was affected by these huge events.

Both World Wars affected the train network in two ways, firstly the network wasn’t expanded during the years of combat because money was funnelled into the war efforts. Secondly, the network was damaged by bombing raids in 1945 and the Nazis may have deliberately sabotaged the key Nord-Süd Tunnel (North-South Tunnel). This tunnel passes under the centre of the city and is used by all the S-Bahn trains that travel between the north and south. It was restored by 1947 so that the northern and southern residents had easy access to central Berlin again.

Potsdamer Platz, one of the Geisterbahnhöfe / Ghost Stations during the Cold War

The Cold War and the building of the Berlin Wall in 1961 immediately impacted the transportation of Berliners with the West Berliners unable to step out into the East and vice versa. This led to the trains driving through many inner city stations without stopping – the so-called Geisterbahnhöfe (Ghost Stations). It must have been very unnerving when the trains would pass through the darkened stations that would’ve been full of East German soldiers!

An S-Bahn strike was started in 1980 by the residents of West Berlin also heavily impacted the public transport network. West Berliners boycotted the S-Bahn, as its fares were seen to be funding the communist regime in the East, and preferred using the U-Bahn and buses run by the BVG instead of the S-Bahn which was then run by the Deutsche Reichsbahn. This huge decrease in passengers led to a reduction in S-Bahn services until reunification in 1990. I didn’t know of this history until reading up on this for the Grand Tour and I didn’t appreciate just how effective the strike was until creating the gif!

The Wernerwerk Station that was part of the Siemensbahn line

The S-Bahn strike led to many of the stations falling into ruin, so much so that after reunification many stations needed serious refurbishment. The cost for these works did not make fiscal sense for some lines and so these were not reinstated. An example is the Siemensbahn, which ran between Jungfernheide and the Gartenfeld station in the Siemensstadt district. The stations and tracks of the Siemensbahn are still standing and provide some great photo opportunities.

Shoutout: I couldn’t have created the gif without the berliner-linienchronik website. This site has records of the transport routes throughout the years – a true treasure trove. There are also examples of the public transport maps from different years. It was very interesting to see how the design of the network changed. Some of the background colour choices are best not revisited! 

Individual Route Analysis

Inspired by the analysis of which districts I cycled in each Stage, I wanted to perform similar calculations focussing just on the public transport routes. This would show how the different districts of Berlin are serviced by different transportation. 

Percentage of public transport route in each district

Looking at all the routes (i.e. buses, trams, U-Bahn and S-Bahn), the central district of Mitte has the largest percentage of public transport routes passing through (3.7 %). This makes sense since all the S-Bahn routes pass through Mitte and it is the centre of the city too. The percentage of public routes in the districts then radiates outwards until the border districts which typically have the least options for public transport routes (usually just buses or trams). 

I thought it was interesting that Köpenick has a relatively large percentage of public transport routes (3.0 %). This is noteworthy because Köpenick is not a particularly central district but it is a tram hub – nearly half of all the tram routes in Berlin pass through Köpenick! 

Unsurprisingly, buses make up the bulk of the public transportation in Berlin (nearly 68 %) and in the districts further away from the centre of Berlin, the importance of buses increases. The districts of Lichterfelde, Marzahn, Tegel and Rudow have the largest percentages of bus routes (2.6 %, 2.4 %, 2.3 % and 2.4 % respectively). I was expecting Spandau to feature prominently here since this is a large transport hub, but the U7 U-Bahn and the S-Bahn lines provide non-bus options for people to get to Spandau.

The bus terminus at Tegel airport, which closed at the end of October 2020

The large amount of bus coverage in Rudow and Tegel can be explained by the airport services towards the Schönefeld and Tegel airports. This will most likely change now since Tegel airport has closed. Marzahn has the largest bus terminus in the east of Berlin (6 bus routes have a terminus here), which helps in connecting people between the S-Bahn, trams and buses to other nearby areas. 

The large amount of kms covered by buses passing through Lichterfelde is a bit harder to explain. It’s not because of the lack of S-Bahn connections – the S1, S25 and S26 all run through the district. The population density in this district is not significantly higher than other districts either. In fact, the population density of a district does not correlate with the amount of public transport running through the district at all (correlation coefficient of 0.3). A plausible explanation might be that it is a rich district. The southwestern borough of Steglitz-Zehlendorf, of which Lichterfelde is part of, has the highest median income in Berlin. (Link in German)

Trams at the Riesaer Straße terminus in the Eastern district of Hellersdorf

Another non-surprising discovery is that trams primarily play a role in the east of Berlin, as these were the public transport of choice when the city was split. While buses were the choice of the West. In fact, the Metro buses (these buses run more frequently and all day, unlike the numbered buses) only run in the west of Berlin – not a single Metro bus passes in a district of former East Berlin. On the other hand, some Metro-trams do pass into the former West Berlin but only because the tracks were extended to do so. And mainly to increase the connections to the Berlin Hauptbahnhof (Berlin Central Station).

Blood Glucose

The next thing I want to look at is how my blood glucose was throughout the Grand Tour. As a Type 1 Diabetic, looking after my blood glucose is key but also a fine balance between keeping “stable” blood glucose and fuelling the body to work efficiently. 

Let’s look at the recommendations for Type 1 Diabetics during exercise (especially cardio): 

  1. Start exercise with a higher blood glucose than usual – say about 180 mg/dL. 
  2. Make sure not to have too much insulin on board to avoid the blood sugar tanking and causing a nasty hypo. Anything lower than 50 mg/dL would be a call to stop and wait for the blood glucose to get above 90 mg/dL.
  3. Don’t let the blood glucose run too high, as this can lead to a dangerous build up of ketones in the body. So avoid blood glucose levels higher than 250 mg/dL.
  4. Check blood glucose regularly.
  5. Always carry emergency fast-acting and slow-acting carbs. Have fast-acting (or bolus) insulin to bring down high blood glucose.

On top of these requirements, there is also the need to fuel the body (i.e. take on carbs) for the physical activity. Running out of energy stores is not fun – I’m sure most cyclists know the feeling of the dreaded bonk/ hitting the wall/ etc. So keeping on top of nutrition, especially for the longer stages, was also important.

Based on all these requirements, a great ride would be one with stable blood glucose and within the range of 80 – 180 mg/dL for the whole stage. In general, I’d say that the shorter stages were much easier to keep my blood glucose stable than the longer ones. I correlated the distance with the range of my blood glucose values for each Stage and this gave a correlation coefficient of 0.53 – so a moderate correlation. So more time in the saddle means more variability in blood glucose levels. 

My blood glucose values during Stages 4 and 47. Green is good!

Stage 47 was the positive exception to this. It was a 93 km long Stage and the range in blood glucose was only 93 mg/dL – nice symmetry right there! I remember how wonderful it was to check on my CGM and see very stable blood glucose. This stability also contributed to how great my legs felt during the Stage. It’s amazing when everything works right!

On the other hand, Stage 4 was the negative exception. A blood glucose range of 165 mg/dL during the shortest Stage of the whole Grand Tour (35 km) is not good. The reason for this instability was that I raced on Zwift the day before this Stage, so my body was very insulin sensitive making it harder to judge the right amount of insulin to have on board when starting this Stage. 

Looking at the range of blood glucose values certainly gives an indication of how stable the blood glucose was during a ride, but not the whole picture. Another aspect is whether there were large swings in blood glucose values – either from low to very high or from high to low. A large swing in blood glucose feels pretty horrible and indicates that I made a bad decision in managing my blood glucose. This can also lead to hopping aboard the dreaded blood glucose rollercoaster! Usually started by injecting too much insulin for high blood glucose, leading to low blood glucose which makes you overeat and high blood glucose, and then …. you get the picture 🙂

The largest swing in blood glucose during Stage 38 is the difference between Maximum and Minimum 2

I decided to look at the blood glucose data for each Stage and determined the values of each maximum and minimum in blood glucose. I then took the difference between the consecutive maxima and minima (and vice versa) to see what the largest decrease (and increase) in blood glucose was in each stage. I’ll call this the swing in blood glucose from now on.

Stages with the Largest RangeStages with the Largest Swing
Stage 50 – Tubegate and BolusgateStage 38 – Queen Stage
Stage 55 – Sale AdviceStage 50 – Tubegate and Bolusgate
Stage 36 – Cobbles and HyperglycaemiaStage 43 –  Swan Stream

You can already see that besides Stage 50, the different metric results in a different view of the Stages. Stage 50 was a particularly nasty one in terms of blood glucose management as I forgot to inject bolus insulin for breakfast before leaving. This automatically nullified any chances I had of meeting the requirements for good blood glucose! 

Stage 38 was the longest Stage of the Grand Tour so blood glucose management was important but also challenging. On the whole, my blood glucose was pretty good except when I ate too many carbs without taking on insulin leading to an increase of 200 mg/dL! I remarkably corrected this with the correct amount of bolus insulin (factoring in the effort levels of the remaining distance) to bring this back to within range. So all in all, I think I did a pretty good job!

The Birkenwerder station from Stage 38 – a nice view while fuelling for the remainder of the Stage

These large swings in blood glucose also affect my physical performance and general mood when cycling too. A drop or surge of 100 mg/dL (or more) in blood glucose level in a short space of time feels pretty terrible. If it’s a surge, I find myself feeling more sluggish and being more irritable in how I react to situations, like say a close pass by a vehicle or if Nadja asks me something. On the other hand, a sudden drop can make me feel weak and light-headed. So avoiding these swings in blood glucose is in my best interest but it’s also important to realise that this is not always possible. Best thing here is knowing how to deal with these swings and treat them appropriately i.e. obey Rule #5. Perhaps a niche take on the other Rule #5.

The most important thing with regards to my blood glucose control while cycling is using a CGM (Continuous Glucose Monitor). The system transmits my blood glucose values to my phone every 5 minutes and alerts me when it’s too low / high or dropping / rising too fast. I can’t stress enough how important it is to be able to react before things get too low or high. Plus I can check on the go and not have to stop for a finger-prick reading. 

The wonderful Bierpinsel / Beer Brush building in Steglitz – part of Stage 57

Stage 57 proved how crucial such a device is. During this Stage, I broke Rule #2 and had too much insulin on board. This meant that I needed to constantly eat to keep my blood glucose within range. With my CGM, I knew that this was happening so I managed to take on sufficient carbs without going hypoglycaemic. I couldn’t have done this Stage safely without my CGM. 

Interestingly, while these Stages (and days) are physically very difficult, it’s hard to calculate a metric that would pick this Stage out as a difficult one for blood glucose control. In fact, it looks like a very good Stage in terms of blood glucose but it was anything but that! 

On a positive note, there were 10 Stages where my blood glucose was within range the whole Stage! Granted all of these were less than 60 km in length (besides the fabled Stage 47), but still these victories are to be savoured. 

Blood glucose management takeaways:

  • CGM is critical.
  • Follow the rules.
  • Be prepared when things go wrong.
Timing fuelling with an ice cream stop is highly recommended!

Recap of the Recap

I’m very proud that I finished the Grand Tour de Öffentliche Verkehrsmittel. it certainly fulfilled my wish to see areas of Berlin that I hadn’t before. I definitely feel that I know the city more than I did before. 

After cycling all the routes, I can say that most routes take passengers from residential areas, typically by bus or tram, to the nearest U-Bahn or S-Bahn stations. Hospitals are also given preference in route planning. Shorter circular bus routes are used for industrial areas or in the border districts, like Kladow and Karow, increasing the mobility of its residents.

A well-hidden gem of a Starling mural – worth keeping an eye out for!

Finally, here are my tips when tackling such a Grand Tour:

  • Speed is not important – take in all the different areas of Berlin, the architecture can differ wildly between streets and districts – appreciate all that!
  • Keep an eye out for fantastic street art.
  • Be careful of people getting on/off buses and trams.
  • Stay off the main roads when not covering public transport routes.
  • Be prepared for anything.
  • Plan a coffee stop – if possible while visiting a friend.
  • Make sure to have enough food.
  • Always inject bolus and basal insulin before leaving – if you have Type 1 Diabetes.
The Landwehrkanal / Land Army Canal

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