Operating The Train Questions

Frequently Asked Questions

2. OPERATING THE TRAIN QUESTIONS

How do I used the different braking systems?

Like a real train, TM4 offers three different braking systems, dynamic brakes, independent (locomotive) brakes and automatic (train) brakes.

Dynamic Brakes use the locomotives traction motors as generators which drive a bank of resistors that turns the energy into heat.

Independent Brakes use air pressure to control brakes that operate only on the locomotive itself.

Automatic Brakes use air pressure to control brakes that operate on the entire train, including the locomotive.

Dynamic brakes are useful for limiting the train's speed over long periods of time, such as descending a grade. They work best at medium speeds; for example, the manual for the EMD SD-40 locomotive states that maximum braking strength is obtained between 18 and 25 mph. At low speeds the dynamic brakes become ineffective since the braking action is dependent on the wheels turning the traction motors.

To use the dynamic brakes first gradually lower the throttle to idle. Then you must pause before proceeding (the SD-40 manuals specifies a 10 second wait). You can then push the button to enable dynamic brakes and use the throttle to control the amount of braking desired.

Automatic brakes are used to slow and stop the entire train. They work by controlling air pressure in lines that go from the locomotive along the entire train. Normally when travelling you would have the brake lever in the left position (release). When brakes are needed move the lever to the right to the service position. This releases air from the equilizing reservoir in the engine which in turn releases air from the brake pipe travelling the length of train. Releasing pressure in the brake pipe causes pressure to increase in the brake cylinder thus applying the brakes to the wheels. You can control how much braking you get by moving the lever from the service one position left to the lap position. This position holds the braking level at the amount set while the lever was in the service position. If you need more braking move the lever back to the service position to increase the brake cylinder pressure to the desired level.

The automatic brakes also have an emergency position which causes the pressure in the brake lines to be released instantly causing maximum braking action as quickly as possible.

The automatic brakes can be used at the same time as the dynamic brakes if necessary.

Independent brakes work in a similar manner to the automatic brakes except they only set the brakes on the locomotive. The independent brake control works differently too, in that you don't need to switch from service to lap to set the desired amount of braking you just move it a step at a time to the right until the desired amount of braking is obtained and move it all the way to the left to release ("bail off") the brakes.

THE SPEED LIMIT KEEPS CHANGING UNEXPECTEDLY AND STOPS MY RUN. I'M TRYING TO FOLLOW THE SPEED LIMITS IN THE MANUAL BUT IT'S NOT WORKING. HOW EXACTLY DO THE SPEED LIMITS WORK?

The problem is that the speed limits listed in the TM4 manual and the actual limits coded in the routes do not match. To add further to the confusion, most of the routes described in the manual are longer than what is actually included in the routes you can drive so you also have to figure out what part of the chart actually applies.

The manual also says that you will receive warnings of speed limit changes on the status line in the middle of the screen. Unfortunately, this is not always true...some routes have it and some don't. You cannot rely on this warnings.

One solution is an independently developed route chart that matchs the actual encoded speed limits. You can download this from the TM4 Forum here at Train-Sim.Com

One other solution is to turn off speed limit enforcement in the TM4 setup menu.

How can I learn what the signals mean?

TM4 uses realistic signals, but there are quite a large number of them for the new engineer to learn. They are all shown in the TM4 book, but over several pages so they are not convenient to reference.

The answer is available in a single page signal reference which you can download here.

Download the signal reference.

Along the side of tracks I see signs with just a "w" on them. what do they mean?

The "W" stands for "whistle". Generally, there is a road just up ahead and you need to sound a warning with your horn.

What is the proper way to get a train started from a dead stop?

There is some technique in getting a train to initially move, especially if dealing with a long freight.

First, you must have the brakes fully released. In a real train this can take as long as 10 minutes! Watch the pressure gauges and wait until the brake cylinder gauge is at zero.

With the brakes off move the throttle control to notch 1. A heavy train will not yet start to move so every few seconds advanced by another notch until movement begins. Though TM4 does not simulate it, in a real train care has to be taken to not accelerate too fast until the train is stretched (all the slack has been removed in the couplers and draft gear). So, for greatest realism back off a notch or more if acceleration is too rapid. Once the train is stretched advance the throttle as desired.

This information is based on the Electro-Motive Division SD40-SDP40 Operator's Manual.

Once moving, how do I accelerate the train?

There is some technique involved in accelerating properly. In general, you can advance the throttle as rapidly as desired. However, using the loading meter (the large meter indicating amps) is the best guide. Each time you advance the throttle the amps reading will go up but after a moment will go back down somewhat. At this point the motors are ready to absorb more power and you can advance the throttle another notch. This technique gives you maximum acceleration without slipping.

This information is based on the Electro-Motive Division SD40-SDP40 Operator's Manual.