See also https://bathtrams.uk/8th-in-sequence-of-tram-letters-in-bath-chronicle/

Dear Chronicle

Lawrence Sanders’ letter suggesting trolley buses for Bath was interesting so it is worth explaining the fundamental difference between a tram and a bus. ( trolley or diesel, or electric bus)

What it comes down to is that trams are expensive to buy, but cheap to operate on each trip.

So once you have bought enough trams to meet the peak demand and the track, they may as well be operated continuously. This is why Trams can operate throughout the day at 6 minute intervals. 2 minutes in Budapest. There is no benefit in leaving them in the depot with idle drivers.

On the other hand, buses ( trolley, bendy bus etc) are very expensive to operate per trip, because whilst the vehicle is cheap they also have expensive tyres, suspension, engines etc to maintain. They also have the high cost of the driver to share over far less passengers. This means there is an incentive to have longer waits between buses, in order to build up sufficient passengers waiting at the bus stop to pay for the costs of the trip, mainly the driver. This also makes makes an incentive to cram as many passengers into the bus which is why they have bench seats but which passengers don’t like being forced into close sitting proximity with others.

On the other hand a tram there are fewer bench seats and are more like an underground train and it is perfectly acceptable to stand and move around, because there isn’t the jerk and vibration of a bus.

This ability to stand and move nearer the door before stopping, as in the tube, means tram boarding times are much lower than a bus making for greater speed and punctuality which are attractive to motorists and the operators.

Another important point is the granting of priority to trams. Highway authorities are unwilling to grant priority to buses because they carry only a low percentage of rush hour traffic and generally sad to say people with low political influence (or perhaps the old who do not pay!). They get too many complaints from the influential car lobby who complain when they are stuck in traffic and see the occasional bus passing down an otherwise empty bus lane.

On the other hand it has been shown that trams gain a significant proportion of previous car drivers (whereas it has been shown that buses do not) so trams can get priority easily even with on-street running.

For the same reason green Wave traffic light priority is generally applicable to trams but not to buses. Green Wave permits trams to move quickly through traffic partly because they concentrate many passengers into a single vehicle. To get the same capacity as a tram line would require 5 times as many buses and this would entail too many traffic light interruptions for it to be worthwhile.

These are the techno-economic reasons why buses including trolley buses are not a solution to Baths traffic.

There is strong evidence around the world and in the UK to support this (all well referenced on the Bath Trams website, but perhaps the most convincing is what happened when trams were removed from Liverpool, Sheffield and London.

In all cases there was an immediate drop of 30% in total passenger numbers because travellers did not find the bus service an acceptable replacement and found other means of getting about – typically purchasing a car. The publicly given reason was to avoid them causing traffic congestion but in fact what happened was an immediate increase in congestion as more cars took to the road!

The other very important point where Lawrence Sanders’  letter is wrong is in claiming that flexibility is a good thing. At first glance this would seem to be obvious but in fact it is not true at all. It’s only too obvious by reading the Bath Chronicle that bus routes change frequently to suit the operator so no developer plans to build a business or a housing estate based on the assumption of a bus.

On the other hand a tram line is fixed and will remain installed for the far future. This is very attractive to developers and house owners. Houses near a tram line attract a premium because the tramline is inflexible.

Trolleybuses need fixed wires so their route is no more flexible than that of a tram. So they lose the flexibility advantage, without gaining the “permanent route” advantage of a tram because there are no rails.

This is why many of the suburbs of Bath such as Twerton and Oldfield Park were provided with a tram by the developers – specifically to make them more attractive. It’s the same reason the Metropolitan tube line was built by the developers who turned the farmland into housing estates in London. And in fact it is how generally all large cities originally developed along tram lines.

Trolleybuses use rubber tyres on tarmac roads. They therefore produce as much Oslo effect pollution as diesel buses from tyre and road wear, equal to the emissions from the exhaust. In fact, if batteries are used to go “off-wire” they produce more pollution due to increased weight.

Kind regards

Chris Donovan

Dear Editor,

I am not an expert in public transport but I am a daily user of the same and have followed the campaign to reintroduce trams with great interest for a long time.

There seems to be in the main a dispute, not about do we need a better system in Bath, but on how to achieve it. The entire financial model around buses and trams is different so comparison is not straightforward. Yes busses are easy to put on, but they are expensive to run meaning there is always the pressure from the accountants to reduce the costs, whether by cutting a service completely or reducing its frequency. The result is just when you think you have found a useful bus service it is changed to your disadvantage. Bus services into and out of Bath are of very different quality. Currently as a commuter I find it much better to catch a bus from the west of Bath to Bristol and catch the train at Temple Meads as the earliest bus service into Bath means I can’t catch a train before 7 am.

Trams on the other hand are expensive to install but very much cheaper to run, in particular when the costs of vehicle maintenance, replacement and the life of a tram compared to a bus are factored in. This means that there is little pressure from the accountants cut trams running of peak as there is little savings to be had.

As to the argument about the track and track installation costs, if the shallow longitudinal beam is used as proposed rather than the traditional sleeper type track the cost savings surely are massive. The matter of utilities does of course have to be addressed, the claim is made that they must all be dug up and re-routed and at the cost of the tram company. Well if you were to put in the deep sleepered track as has been done in many places then yes, but do we need tram tracks capable of carrying a thousand tonne freight train as is the case apparently in Edinburgh? The utilities on the other hand should be well below the depth needed for the longitudinal shallow trench and beam now apparently available. Surely there are regulations about the minimum depth of the utilities? If they are not at such a depth then the utility company should move them at their expense. I suspect, but cannot substantiate, that there are those who just wish to get the utilities replaced at somebody else’s expense. As to the questions about digging up the road for work on the utilities, how often does that actually occur? Nearly all the work in my area of late has involved digging up the pavements.

Pollution is of course the other big issue and again trams would seem the obvious solution, electrically powered and not producing the exhaust, tyre and brake dust that busses of whatever type do, we are it seems only just publicly learning about these additional sources of harmful particles, PM10s and PM5s, even PM2.5s the so called Oslo effect which according to some scientists contribute as much pollution as from the actual vehicle exhausts and which are entirely absent with trams. Trams also have the advantage of not wearing away at the roads causing or worsening existing potholes and rutting.

Chris Shire

Dear Chronicle,