Frequency is not just about increasing the number of trains..... You see you don't just begin with axle load or Horse Power etc... They start with
how much cargo do you need to be transporting per year and
what type of cargo will it be...
Then depending on those two major factors, is when you can end up with the conclusion on frequency, axle-load, speed etc
For Kenya's case,
- They probably started with a user requirement of 20 million tones railway (They made it 22 million just to be on the safe side).
- Then they saw that the main type of cargo will be containerized cargo, and bulk/loose cargo like fuel,cement..etc basically no extra heavy metals are available in Kenya... So their calculations ended up concluding that 25t axle load is more than sufficient for 99% of Kenyan cargo.
- After knowing the amount of tones and the type of cargo, That's when they decide which frequency best serves the customers. Do you need a few powerful trains with low frequency or many trains doing higher frequency. They then concluded that since its mostly container cargo, its best if smaller trains leave every 3 hours rather than larger trains be forced to wait at the port for 8 hours to be full .. So higher frequency was chosen. now how do you have higher frequency on a single track railway? By building more side loops at short intervals (every 30 km if I remember correctly) to enable more trains to pass each other in order to enable the high frquency.
As For Tanzania's case....
- They started with a user requirement of 15 Million tones (They made it 17 million just to be on the safe side) as the projected cargo that will use rail after careful consideration.
- They were probably thinking of heavy metals and raw mineral deposits found in both Tanzania and DRC.. So they ended up concluding that you need heavier load per train because mineral deposits are heavy and can be accumulated over time and then be carried all at once.. That's how they arrived at 35t axle load as sufficient enough to carry heavy minerals without damaging the rail.
- After knowing the amount of tones and the type of cargo, That's when they decide which frequency best serves the customers. So as opposed to Kenya's case, they concluded that since its mostly heavy minerals that can be accumulated and carried at once, you don't need that many trips in a day. So you can have a train leaving every 8 hours but carrying double the cargo..
Kwahivyo hii mijadala ya axle load, loop lines/sidings, Horse power, length of train ....... These are not the main points, these are just the enablers, the main objective is/was tonnage and type of cargo.... We can argu all day about nitty gritty issues like speed, technology,..etc but at the end of the day, how much cargo you carry is all that matters..
Alafu BTW SGR ya Kenya inaweza kufikisha 35 million tonnes after upgrade
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Kwenya feasibility report wachina walisema kama tunataka kufikisha hio 35 million tonnes, itabidi tufanye electrification, treni ziongezwe kutoka 45 hadi 100, alafu loop points ziongezwe kutoka 30 hadi 42 kama sijakosea i.e itakua treni zinaweza kupishana every 15 km .. Lakini reli itabaki ile ile, ni vile tu itakua imeongezewa maridadi, lakini tayari vile ilivyo hio reli yenyewe imejengwa na uwezo wa kubebesha maximum of 35 million tonnes itakapofanyiwa upgrade, but at current design, 22 Million tones is the maximum.